126 A REVISION OF THE ASTACIDA. 
appendages of the male are neither bifid nor toothed at the tip, and there 
are no hooks near the base of any of the thoracic legs. 
The Astaci from Western Asia curiously simulate the Cambari of North 
America in the general shape of the subeylindrical body and in the form 
of the chelipeds. The second and third pairs of thoracic legs of the male 
bear hooks on the third segment similar to those of the male Cambarus, 
and the first pair of abdominal appendages are terminated with short teeth. 
The three Asiatic species, A. Japonicus, Dauricus, and Schrencki, thus form 
a second natural group, combining some of the characters of Astacus and 
Cambarus. This group I have called Cambaroides, 
Suscenus CAMBAROIDES. 
Cephalothorax subcylindrical. Last thoracic segment bearing a pair of 
pleurobranchix. Third segment of second and third pairs of legs of the 
male hooked. First pair of abdominal appendages of the male terminating 
in short teeth or tubercles. 
The three species Asfacus Juponicus, Dauricus, and Schrenckit, from Japan 
and the basin of the Amoor River, widely separated from the rest of their 
family im geographical position, form a natural group of subgeneric value, 
to which I have given the name Cambaroides. In them is found a com- 
bination of characters of Astacus and Cambarus. In the general appear- 
ance of the body, with its subeylindrical cephalothorax, and in the form 
of the rostrum and chelipeds, these Asiatic Astacidz strikingly recall the 
Cambari of North America, and their affinity is made more evident through 
the hooked thoracic legs and tooth-tipped sexual appendages of the male. 
The hooks are situate, in all these species, on the third segment of the 
second and third pairs of legs, as in Cambarus Montezume and Shufeldti. 
The rostrum is devoid of lateral teeth. The carpus is armed with a strong 
median internal and an anterior inferior spine. The external flagellum of 
the antennules is serrate below, each segment being produced at its antero- 
inferior angle, which bears a bundle of eight or ten of Leydig’s olfactory 
organs. These are arranged in a single group on each antennulary segment, 
instead of being distributed into two bundles, as in Cambarus and Astacus 
proper.* The front border of the carapace is strongly angulated behind the 
* The same arrangement of the olfactory sete is found in the Parastacine. 
