ASTACID^E. 33 



length of the antennae equals that of the body, or exceeds it ; their 



lamina is elongated, and dilated near the base : the basal joint of the 

 inner antennae has an interior spine before the middle. The foreborder 

 of the cephalothorax is angulated behind the antennae. 

 In C. troghdytm burrowing habits are observed. 



It is worthy of remark that in the considerable number of females 

 Been by me. eggs are in no instance attached to the abdomen. Perhaps 

 the females live more retired now than formerly, and are not easily se- 

 cured. I have seen many females of various species of the other groups 

 with eggs attached to the abdomen. 



The species contained in this group are divided into four natural 

 sections, having the following characters: — 



1. The rostrum is broad, very long, triangular, with a small spine 

 near the extremity, somewhat, but very slightly, developed (always 

 strongly developed in the young) : the postabdomen is as long as the 

 thorax ; the hands are elongated ; the antennal lamina is long, and 

 enlarged near the base. — O. aeutus and allied species. 



2. The rostrum is broad, very long, triangular, with a strong and 

 acute apical tooth on each side ; the postabdomen is longer than the 

 thorax ; the hands are elongated ; the antennal lamina is long, and en- 

 larged near the base. — 0. spicuUfer and allied species. 



3. The rostrum is broad, triangular, not so much elongated, without 

 ante-apical teeth (always developed in the young); the postabdomen as 

 long as the body ; the hands are shorter, broader : the antennal lamina 

 is shorter, and enlarged near the tip. — C. pemeUMuis and allied species. 



4. The rostrum is broad at the base, very long, with a strong and 

 acute tooth each side ; the postabdomen is longer than the thorax ; the 

 hands are elongated : the antennal lamina is long, and much enlarged 

 near the tip. — 0. pellucidus. 



The most aberrant species is C. pellucidus. Like the other animals 

 living in caves, it is blind. The eyes are atrophied, smaller at the base, 

 conical, instead of cylindrical and elongated, as in the other species. 

 The cornea exists, but is small, circular, and not faceted : the optic 

 fibres and the dark-colored pigments surrounding them in all other 

 species are not developed. The shape of the rostrum is somewhat 

 analogous to that of C.affims,HhQ margins are more parallel at the base. 

 The lamina of the antennae is long, but strongly dilated nearer to the 

 tip : the epistoma is shorter and broader than in the other species; the 

 basal joint of the inner antenna? has a spine at the tip, which in the 

 other species is always nearer to the base ; the foreborder of the 

 cephalothorax is not angulated behind the antennae as in all other 

 species. 



Nevertheless, the number of the hooked legs, the form of the abdom- 

 inal legs, and the elongated body and hands, exclude C. petturidw from 



