CRAYFISHES. 393 
100 mm. in length according to Banta, while those from the outside do not exceed 
84 mm. A series of fifty-eight specimens from the outside waters compared 
with a series of six specimens from Mayfield’s Cave, Monroe Co., by Mr. Banta 
revealed the fact that the antennae of the cave specimens averaged 11.89 p. ec. 
longer than the antennae of specimens taken outside the caves in the immediate 
vicinity. The cave series was also lighter-coloured than the series from above 
ground. 
CAMBARUS GRAYSONI, sp. nov. 
Cephalothorax robust, posterior section high, flattened on the back and 
compressed laterally so that the sides are nearly vertical, giving to the whole 
section a subquadrangular aspect; shell densely punctated on the dorsal face, 
granulated on the lateral surfaces; distance from the tip of the rostrum to the 
cervical groove one and one half times the length from the cervical groove to the 
posterior end of the carapace; there are no lateral spines upon the carapace 
and only the rudiments of the branch ostegal spines; the areola is narrow (1.5 
mm. broad at the middle in a specimen measuring 21 mm. from the cervical 
groove to the posterior border of the carapace) with but two rows of dots along 
the narrow part of its course; rostrum short, margins slightly convergent, middle 
excavated, acumen short, upturned at the tip, without lateral spines or teeth; 
post-orbital ridges low, without spines; sub-orbital angles well marked but 
blunt. 
Abdomen as long as the cephalothorax, smooth, pleural angles rounded. 
Chelipeds short in proportion to the body; merus short, with low tubercles 
near the distal end of the superior margin and spines biserially arranged on the 
lower face; carpus deeply furrowed along the upper face, armed with a 
prominent median internal acute thorn or spine, one or two small tubercles in 
place of a median posterior spine; an inferior median spine, with sometimes a 
small tubercle between it and the interior median spine completes the armature 
of the carpus; the chela is short, broad and triangular, articulated with the carpus 
in such a way as to assume a vertical position when flexed and to form with its 
fellow a shield or operculum appressed to the front of the body; this conforma- 
tion of the chelae is a sure token of the burrowing habits of this species; the inner 
(or superior) margin of the palm, is very short, with a marginal row of five or six 
low tubercles; immediately within this row (which forms a serrate edge to the 
hand) is another row of similar though smaller tubercles, with vestiges of a few 
more irregularly disposed near the articulation of the dactylus; the fingers 
