CAMBARUS. 67 
C. montanus, the antennxe were longer, the rostrum was more tapering and 
terminated in a more elongated point, and the areola narrower. This was 
probably a form of C. Barton’, whether identical with Rafinesque’s C. pu- 
sillus or no is doubtful. 
C. robustus Girard, not an uncommon form in the St. Lawrence valley 
about Lake Ontario, is so near to C. Barton that it is best treated as a 
variety of that species. The differences are sufficiently pointed out by 
Hagen on page 80 of the Monograph of the North American Astacide. 
They are hardly greater than in some of the varieties of C. Bartonii noticed 
above. Both forms, C. robustus and the typical C. Bartonii, are found to- 
gether in some parts of New York State. A male specimen in the collection 
of the Academy of Natural Sciences of Philadelphia, from Humber River, 
Toronto, is probably one of Girard’s types. There is a male specimen from 
Decatur, IIl., in the collection of the Boston Society of Natural History, and 
two small specimens from Tennessee, Dr. Curtis, which appear to be C. 70- , 
bustus. In the Philadelphia Academy there is also a young specimen from 
Florida that resembles C. robustus, but the antennal scale is broader at the 
tip. C. Bartoui, var. robusta, is also found in Virginia. I have seen speci- 
mens 86 millimeters in length. 
The first abdominal appendage of the male C. Bartonii’, var. robusta, is 
figured by Brocchi, Ann. Sci. Nat., 6° Sér., Zool. et Paléontol., H., Pl. XIII. 
fig. 15. 
In the Report on the Crustacea of the United States Exploring Expe- 
dition (Pt. I. p. 525, Pl. XX XIII. fig. 2) Dana describes and figures as 
Astacus (Cambarus) Barton a crayfish of uncertain locality, “ possibly from 
Brazil.” It is clearly not Cambarus Bartoni’, neither is it the same as the 
Brazilian Parastacine crayfish in the Museum of the Academy of Natural 
Sciences of Philadelphia, as Hagen suggests (p. 11). I have not been able 
to find Dana’s type in the collections of the Smithsonian Institution. 
23. Cambarus acuminatus. = \. Parienn atu: 
Plate III. fig. 5, Plate VIII. figs. 6 a, 6 a. 
Cambarus acuminatus, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 113, 1884. 
Rostrum long, tapering, ending in a long, sharp acumen, without lateral 
spines; upper surface smooth, somewhat hollowed out, margins punctate, 
ciliate, raised into low sharp crests. Post-orbital ridges with sharp anterior 
