ASTACIDJE. 43 



The specimens before mentioned, from Georgia, are not essentially 

 different, though the thorax is more compressed. The female has the 

 areola larger. Some females from Charleston have the lamina also 

 trispinose. It seems not prudent to separate the two species, for the 

 materials are insufficient. 



A single male, the largest seen by me, was in the same bottle with 

 A. obesus, from Lawn Eidge, Illinois. 



The posterior hooks of the abdominal legs of the male exist in the 

 young males, Forma II. ; in the very young they are sometimes ab- 

 sent ; sometimes they disappear. The fingers are not arcuated in 

 the younger male and female specimens. 



A large female (dry), in the Cambridge Museum, communicated by 

 L. R Gibbes, as A. Blandingii Harl. from South Carolina, is A. troglodytes. 



A. fossarum LeConte. A dry specimen (Mus. Philacl.), a female, 

 agreeing very well with the description, does not differ from A. troglo- 

 dytes. It possesses the same compressed thorax, like the specimens 

 from Georgia. 



C. Blandingii (Mus. Philad.), from Charleston, is a male, Forma II., of 

 C. troglodytes, and perhaps a type of C. Blandingii Girard. 



Cat. No. 182, Charleston, S. C, L. Agassiz. Male Form I. and II. Fern. 

 Spec. 12* 



Cat. No. 283, Charleston, S. C, Mr. Crady. Male Form I. and II. Fern. 

 Spec. 12* 



Cat. No. 197, Lawn Ridge, Illinois, Mr. 0. Ordway. Male Form I. 

 Spec. 1. 



Cat. No. 1823, Georgia. Male Form I. and II. Fern. Spec. 4. 



Dry spec. South Carolina, L. R Gibbes. Male, labelled "A. Blan- 

 dingiir Spec. 1. 



Rocky River, Olmsted, Ohio, L. Agassiz. Male. Spec. 1. 



Charleston, S. C, L. Agassiz. Male. Spec. 1. 



4. Cambarus Blandingii Harlan. 



Astacus Blandingii Harl, Trans. Amer. Philos. Soc, T. 3, p. 464. Harlan. Med. and Physic. 



Research, p. 229, fig. 1. 

 Figures on PI. I. and III. 

 First abdominal legs of the male : 



first form, fig. 63 in front, fig. 64 outside. 

 Antennal lamina fig. 140, a ; epistoma, b ; spine of the second joint of the exterior antenna, c. 



Mas. Rostro triangulari, lato, laevi, excavato, marginibus summa 

 basi parallelis, lineato-punctatis ; acumine brevi, angusto, acuto, utrin- 

 que subsinuato ; cretis basalibus validis, extus sulcatis, apice subacutis 

 parallelis, postice calloso-convergentibus. Antennis validis, corpore 

 brevioribus (? secundum Harlani figura), articulis duobus basalibus 

 dente acuto externo ; antennis internis articulo basali dente medio 



