CONCHIFERA. 
H6RNESIA, Laube, 1865. 
Dedicated to Director Dr. Moriz Hornes. 
Type, Gervillia socialis, Sckloth, St. Cassian. 
Differs from the typical Gervilliz by the peculiar structure of 
the hinge, and by a more or less lengthened septum going 
through the cavity of the umbones. The genusis intermediate 
between Cassianella and Gervillia. 
NAYADINA, Munier-Chalmas, 1868. 
Type, N. Heberti, Munier, Cenonamian, Aubeterre. 
Shell resembling a transverse Vulsella, rostrated posteriorly ; 
the internal fibrous layer is wanting. 
Huiemus, H. Deslongchamps, 1856. 
Etymology, eAvyos, 2 sinuosity, in allusion to the sinuosities 
of the borders of the post-apical opening. 
Type, i. polytypus, E. Deslong. Fig. 27 
Fig. 27.—Eligmus Polytypua. 
Animal unknown. 
Shell free, or perhaps attached by a byssus, nearly equi- 
valye, inequilateral; ovate or cylindrical, more or less com- 
pressed; anterior extremity inflated, and shorter than the 
attenuated posterior one. Test rather thick, foliaceous. Um- 
bones inflated,’ slightly depressed or: flattened, diverging and 
directed backwards. Valves closed at both extremities, with 
un unsymmetrical (byssal?) sinus, s, behind the umbones; 
ornamented by oblique, radiating carmated ribs. Hinge 
short, straight, edentulous; ligamental area triangular, with a 
superficial pit, 7. Muscular scar single, situated on the free 
67 
