52 



U.S. NATIONAL MUSEUM BULLETIN 29 5 



Figure IS.—Paranesidea spongicola, n. sp.: A-D, Male USNM 121302; E,F, female 

 USNM 121303. 



A,B) Carapace interiors; C, copulatory organ and furca; D, maxilla; E,F, carapace 

 exteriors. A,B,E,F, X 43; C,D, X 301. 



Diagnosis. — Carapace exterior with abundant fine pits and bearing 

 rather numerous small spines, these located mainly in anterior, 

 posterior, and ventral regions and absent from the dorsomedian and 

 median areas. Posterior siphonate indentation of selvage very con- 

 spicuous on both valves. Anterior and posterior margins of both 

 valves with striate frill. Muscle-scar pattern as usual for the genus; 

 anterior to adductor scars is a conspicuous raised crescentic projection 

 similar to the fulcra! point found in some Cytheraceans. 



