Fauna, Bulletin of the New York State Museum, number 49.

Mentions Ampyx halli and Remipleurides canadensis in comparisons. 1902. Raymond, P. E. The Crown Point section. Bulletin of American Paleontology, volume 3, number 14.

Gives lists of Chazy fossils, including trilobites and figures Thaleops ovatus.

EXPLANATION OF PLATES.1

1. Harpina antiquatus Billings.

PLATE 10.

A cephalon, enlarged two diameters. An imperfect cephalon, enlarged two diameters. 3. Lonchodomas halli Billings. A cranidium, enlarged two diameters.

2. Harpina ottawaënsis Billings.

4. The same species. Side view of cranidium, showing the upward slope of the rostrum, enlarged two diameters.

5. The same species. A pygidium and two thoracic segments, enlarged four diameters.

6. Posterior view of the same, enlarged four diameters.

7. The same, side view, enlarged four diameters.

8. Remipleurides canadensis Billings. Side view of cephalon, twice natural size. 9. The same, dorsal view, twice natural size.

10. The same species. Pygidium and last five thoracic segments, four times natural size.

11. Bathyurus angelini Billings. A cranidium, one third larger than the specimen. 12. The same species. A pygidium, one third larger than the specimen.

13. Bathyurellus brevispinus Raymond. A cephalon, enlarged two diameters. 14. The same, side view, enlarged two diameters.

15. The same species, dorsal and profile views of a cranidium, enlarged two diameters.

16. Bathyurellus minor Raymond. A pygidium, enlarged four diameters.

17. Asaphus marginalis Hall. A small cranidium.

18. The same species. Free cheek of a somewhat larger individual.

19. The same species.

20. The same species.

on its posterior end.

A small pygidium.

A slightly larger pygidium showing a peculiar projection

21. Isotelus bearsi Raymond. A cranidium, the eye stalks broken.

22. Front view of a larger specimen of the same species showing eye stalks.

23. The same species. Dorsal view of free cheek.

24. The same, lateral view.

25. A small pygidium belonging to this species.

PLATE II.

An outline drawing of a restoration of Asaphus marginalis Hall. One half the natural size indicated by fragments in the Carnegie Museum.

1 Where not otherwise indicated, the figures are natural size.

PLATE 12.

I. Isotelus obtusus Hall. Outline of a complete specimen.

2. The same species. A pygidium and five thoracic segments.

3. Isotelus harrisi Raymond. An imperfect free cheek, showing the genal spine.

4. The same species. A small cranidium.

5. The pygidium of a large individual of this species.

6. The same species. Hypostoma.

7. Side view of another hypostoma.

8. Asaphus, species alpha. Pygidium, enlarged four diameters.

9. Asaphus, species beta. Pygidium, enlarged two diameters.

10. Asaphus, species gamma. Pygidium, enlarged four diameters.

PLATE 13.

1. Illenus indeterminatus Walcott.

2. The same species. A free cheek.

3. Isotelus angusticauda Raymond. A pygidium.

4.

The same, side view.

5. Thalcops ovatus Conrad. An entire specimen, the test broken from glabella and pygidium. Enlarged two diameters.

6. Illenus globosus Billings. A small cephalon.

7. Thorax and pygidium of a larger individual of the same species.

8. Illanus erastusi Raymond. A cephalon of average size.

9. Pygidium of the same species.

10. Illænus punctatus Raymond. A small specimen, the cephalon distorted by pressure, enlarged two diameters.

11. Ilænus bayfieldi Billings. Cephalon of one of the typical specimens.

12. Thorax and part of pygidium of the same.

13. Proëtus clelandi Raymond. Cranidium of the type specimen, enlarged two diameters.

14. Profile view of the same, enlarged two diameters.

PLATE 14.

1. Platymetopus minganensis Billings. A cranidium, natural size.

2. The same species. A small pygidium, imperfect at the front, one third larger than natural size.

3. The same species. Outline of hypostoma, twice natural size.

4. Glaphurus pustulatus Walcott. A cranidium and part of thorax. Only such spines as show on a single specimen are represented. Twice natural size.

5. The pygidium of a large individual of the same species, enlarged three diameters.

6. The same species. An hypostoma, enlarged three diameters.

7. Glaphurus primus Raymond. Glabella and portion of fixed cheeks, enlarged two diameters.

8. Free cheek of Glaphurus primus, enlarged two diameters.

9. Cybele valcourensis Raymond. The pygidium, enlarged four diameters.

10. Amphion canadensis Billings.

Dorsal view of an entire specimen.

II. Front view of the cephalon of the same specimen.

12. The same species. The pygidium of a larger specimen.

13. The same species. An hypostoma.

14. Ceraurus pompilius Billings. A cranidium, one third larger than natural size. 15. Ceraurus hudsoni Raymond. A cephalon with incomplete genal spines, one third larger than natural size.

16. Pseudosphærexochus vulcanus Billings. An incomplete cephalon, twice nat

ural size.

17. Pseudosphærexochus vulcanus billingsi. Side view of an incomplete cranidium, twice natural size.

18. Pseudosphærexochus approximus Raymond. 19. Pseudosphærexochus chazyensis Raymond.

two glabellar furrows, twice natural size.

A cranidium, twice natural size.
Side view of a specimen with

20. The same species. A small glabella, three times natural size.

21. Pseudosphærexochus (Nieszkowskia) satyrus Billings. Side view of an incomplete cephalon.

22. Sphærexochus parvus Billings. Side view of an incomplete cephalon, enlarged two diameters.

23. Sphærocorphe goodnovi Raymond. A cephalon lacking the genal spines, enlarged two diameters.

24. Pterygometopus annulatus Raymond. A cephalon, one third larger than natural size.

25. The same species. A small pygidium.

VII. THE CRAWFISHES OF WESTERN PENNSYLVANIA.

BY DR. A. E. ORTMANN.

Up to the present time, the crawfish fauna of western Pennsylvania was very incompletely known. Aside from the scanty records given in the monographic works on American crawfishes by Hagen (Ill. Catal. Mus. Harvard, 3, 1870) and Faxon (Mem. Mus. Harvard, 10, 1885), to which Faxon added a few other records (Proc. U. S. Mus., 20, 1898), we possess only a list of the species of crawfishes of Allegheny county, published by E. B. Williamson (Ann. Carnegie Mus., 1, 1901, 8-13). Unfortunately, this list was founded upon entirely insufficient material, and, consequently, later investigations have necessitated a number of changes and additions.

Hagen, in 1870, mentions two species from the State of Pennsylvania, of which one (Cambarus affinis) is said to be found also in the western part, at Pittsburgh (pp. 61 and 100, l. c.). This record, however, has not been substantiated by subsequent investigations; Cambarus affinis being restricted to the eastern portion of the state. Faxon, in 1885 (1. c., p. 165), mentions four species from the state, of which three are also recorded from the western part: Cambarus bartoni, Cambarus diogenes, and Cambarus rusticus. The latter species is said to come from Pittsburgh (p. 110), but, as the writer has ascertained now, this species is not found at Pittsburgh, and has not been found in any other part of the state, although it has been carefully searched for. Thus, the number of species actually known up to that date (1885) is only two, namely: Cambarus bartoni and Cambarus diogenes. In 1898 (1. c., p. 625) Faxon added a third species: Cambarus obscurus, from Westmoreland county.

Williamson, in 1901 (1. c.), gave the following five species from Allegheny county: Cambarus bartoni (and var. robustus), Cambarus diogenes, Cambarus dubius, Cambarus propinquus, Cambarus rusticus. Closer examination of the material preserved in the Carnegie Museum, that served as a basis for Williamson's paper, and its comparison with additional material, reveals the fact that only two of these species were correctly identified (Cambarus bartoni and Cambarus diogenes), while C. dubius turns out to be a new species, and C. propin

quus and rusticus are really identical, belonging to one and the same species, which, however, is not to be called by either name, but is Cambarus obscurus. Consequently, Williamson's list of the crawfishes of Allegheny county really comprises only four species: Cambarus bartoni, Cambarus diogenes, Cambarus nova species (monongalensis), Cambarus obscurus, and these four species are all that were known from western Pennsylvania up to the present time.

Extended collecting excursions undertaken by the present writer during the summer of 1904 have confirmed the presence of these four species in this region (or part of it), and have added two more species: Cambarus propinquus, from Erie and Crawford counties, and Cambarus carolinus, from Westmoreland, Fayette, and Somerset counties.

In studying the crawfishes of this region it was the special object of the writer to ascertain the exact boundaries of the distribution of each species, and, if possible, to correlate these boundaries with physical features of the country. The results obtained, although not yet complete in every respect, have proved to be highly interesting and apt. to throw light upon the postglacial immigration of the freshwater fauna into this part of the state. At the same time, numerous observations on ecology, habits, and life-history of the different species have been made, which shall be set forth in a larger paper comprising the crawfish fauna of the whole state, since, at present, they are too fragmentary to be presented.

The present paper is to be regarded only as a preliminary account of the work done in the western portion of the state. This portion is sharply separated in its fauna from the central and eastern portions and comprises, generally speaking, the drainage of the Ohio River (Ohio, Monongahela, Allegheny), and consequently belongs to the Mississippi system. Only the northwestern corner of the state (parts of Erie and Crawford counties) does not belong here, draining into Lake Erie (St. Lawrence system), but it is included on account of its geographic situation, and the remarkable faunal conditions presented by it. Thus we may say that western Pennsylvania, as understood in the following pages, means that part of Pennsylvania that lies west of the divide between the waters that run to the Atlantic ocean (Delaware, Susquehanna and Potomac), and the waters that drain through the Ohio to the Mississippi and the Gulf of Mexico. This dividing line runs, roughly speaking, through Potter, McKean, Elk, Clearfield, Indiana, and Cambria counties, and thence along the main chain of the Alle