390 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 89 



posterior margin of carapace; length of carapace, measured along mid- 

 dorsal line from tip of rostrum to posterior margin of carapace; width 

 oj rostrum at base, measured opposite the anterior terminals of post- 

 orbital ridges; length of rostrum, from the postorbital ridge to tip of 

 rostrum ; length of areola, measured along middorsal line from cervical 

 groove to posterior margin of carapace; width of areola, narrowest 

 place between the sutures; width oj chela, greatest width of palm. 



CAMBARUS ACHERONTIS Ldnnbere 



Figure 15 



1894, Carnharus acherontis Lonnberg, Zool. Anz., vol. 17, No. 444, pp. 125-127. 

 1894. Carnharus acherontis Lonnberg, Bihang Sveuska Vet.-Akad. Haiidl., 



vol. 20, Afd. 4, No. 1, p. 6, figs. 1-6. 

 1903. Carnharus acherontis Harris, Kansas Univ. Sci. Bull., vol. 2, No. 3, pp. 58, 



67,1 150, 152, 162. 



Diagnosis. — ^An almost colorless subterranean species with unpig- 

 Tuented eyes. The male with bituberculate hooks on the ischiopodites 

 of the third and fourth pereiopods. First-form male without cephalic 

 process on first pleopod, but with subterminal mesial process. A 

 lyre-shaped plateau on the anteroventral portion of the annulus 

 ventralis. 



Male (form T). — Body subovate, flattened dorsoventrally. Abdo- 

 men slightly narrower than cephalothorax. 



Width of carapace in region of caudodorsal margin of cervical groove 

 greater than depth. Greatest width of carapace about midway 

 between caudodorsal margin of cervical groove and caudal margin of 

 cephalothorax. 



Areola narrow, 20 times as long as wide. Cephalic region of cara- 

 pace about 1.45 times as long as areola. Areola sparsely punctate 

 cephalad and caudad. Sides almost parallel for a short distance in 

 middle. (Apex of rostrum broken in male, measurements made to 

 base of apex.) 



Rostrum long, narrow, tapering cephalad. Acumen broken; 

 lateral spines short, weakly acuminate. Small secondary tubercles 

 on each margin of rostrum at midlength. Upper surface deeply 

 excavate. Postorbital ridges terminating anteriorly in short spines. 



Surface of carapace tuberculate laterally; dorsally polished and 

 slightly punctate. No lateral spines. 



Abdomen smooth, slightly longer and slightly narrower than cepha- 

 lothorax. Anterior section of telson with one spine in each of the 

 posterolateral corners. 



Eyes reduced, not pigmented. 



Epistome small, margins slightly elevated, with an anterior median 

 spine; undulating laterally. 



' In part; i. e. excluding "2. Oum Cave, Citras county**'" 



