924 



ZOOLOGICAL SOCIETY BULLETIN. 



considers discretion tlie better part of valor, and 

 escapes if opportunity offers. The method of 

 swimming has two advantages : he presents liis 

 large fighting claws to his enemy while fleeing, 

 and when cover is reached he can enter it hack- 

 ward without stop])ing to turn around and 

 blocks pursuit with his claws. In fighting he 

 possesses some of the qualities of the bulldog, 

 and doesn't always know when to let go. If a 

 stick is poked at him, he may attack it with 

 such vigor that he can be drawn from his retreat, 

 or even out of the water before it occurs to liim 

 that he can release his hold. The species which 

 live on a muddy bottom would seem to have 

 taken a lesson from the Hebrew exodus, and 

 learned to cover their retreat by a ))illar of 

 cloud. In this case, however, the cloud consists 

 of mud which is stirred u\i to such an extent by 

 striking the tail on the bottom that their where- 

 abouts is effectively obscured. When, after a 

 few minutes the mud is settled, the crayfish may 

 be seen half buried under it, his colors com- 

 pletely obscured by it, and his slowly moving 

 antenna? and watchful eyes the most eons])icu- 

 ous jiarts observed. 



In New England crayfishes are not common, 

 and only one species (C. barionii') has been rc- 

 ))orted. West of the Adirondacks and Catskills 

 thev l)Ccome very abundant, and this is espe- 

 cially true of streams having their source in the 

 Alleghenies and in the great central basin of the 

 LTnited States. No less than twenty-five species 

 and varieties inhabit the Ohio River basin, which 

 is ))erhaps the richest area in the world in 

 species of crayfishes. Species are numerous in the 

 South Atlantic and Gulf States, and also in the 

 region of the Ozark Mountains west of the 

 Mississippi. 



In the number of individuals these regions 

 are no less rich than in number of species. A 

 single haul of a fine-meshed seine will often 

 yield hundreds of them. In the writer's ex- 

 perience in collecting fishes in Ohio, the cray- 

 fishes were frequently so abundant as to ma- 

 terially impede the progress of the work. A 

 half-bushel of crayfish would often have to be 

 looked over and the smaller fishes separated 

 from the clawing and snapping mass, and when 

 recovered, were often found injured by the large 

 pincers of their armored fellow captives. 



Thus far only a single species has been re- 

 ported in the region about New York City*. 

 This is the widely distributed Ca7nhnrus harioni 

 (Fabricius), which occurs in eastern Canada 

 and eastern United States south to North Caro- 

 lina and west to Indiana, and which is the onlv 



•Paiilmier. Higher Crustacea of New Yorlc State, 

 Bull. 91, New York State Museum, 1905. 



species reported from New England. Recently 

 the New York Aquarium has obtained an abun- 

 dance of specimens of another species, C. limosus 

 (Rafinesque), from Central Park Lake, New 

 York Citj', and Prospect Park Lake, Brooklyn. 

 This species has not hitherto been known outside 

 of the Delaware, Potomac and Susquehannah 

 river drainages, except for one locality, Redbank, 

 New Jersey, in the New York Bay drainage 

 (see Ortinann's "Crayfishes of Pennsylvania"). 

 Its api)earance in the park lakes of New York 

 City thus extends its range considerably. Dr. 

 Ortmann has called my attention in a recent 

 letter to the fact that this species has been in- 

 troduced into a lake at East Hampton, Con- 

 necticut, and also that it has been naturalized, 

 locally, in Germany. Camharus limosus is 

 essentially a lowland species of the rivers and 

 ponds, while of C. hartoni, Ortmann (1. c, 

 p. 417) says "Ecologically this species is a form 

 of the rapid and cool waters of the uplands and 

 mountains, living preferably in small streams 

 and even in springs," 



Camharus limosus is now abundant in the arti- 

 ficial lakes of New York City. On seining trips 

 to these lakes, made by employees of the 

 Aquarium for the purpose of obtaining fishes, 

 they have been taken readily, sometimes a couple 

 of dozen or more at a haul. Whether they occur 

 in the lowland streams of the vicinitv has not 

 been determined. Neither is it known whether 

 their appearance here is of recent date, or 

 whether they have merely been overlooked. At 

 any rate, there are no records of occurrence in 

 this vicinity, and the study of the specimens in 

 the local museums reveals only very recent 

 captures from these same lakes. 



As to the possibility of recent distribution to 

 the eastward from the Delaware River S3'stem, it 

 would seem that this may have been facilitated 

 by means of the Raritan Canal. In this case 

 their appearnaee in Central Park I^ake would 

 have necessitated the sjiecies distributing itself 

 across the brackish waters of New York Bay or 

 the lower Hudson River, and to get to Prospect 

 Park Lake the East River would also have to 

 be crossed. No crayfishes are found in salt 

 water, however, and this fact would seem to be 

 opposed to such a distribution. Experiments 

 have been made at tlie New York Aquarium to 

 test the resistance of this species to the harbor 

 water, and it has been found that in brackish 

 water having a specific gravity of 1.14 degrees 

 they will live for many days. If investigation 

 should ])rove that the species has distributed 

 itself commonly in ea.stern New Jersey, the 

 hypothesis that they have gained access to the 

 park lakes through the brackish water of the 



