70 



CONCHOLOGY. 



3. Genus Pinna. 

 Jl7iimal. Body oval, elongated moderately thick enveloped in 

 a mantle closed above, open below, and especially to the rear 

 where it forms sometimes a sort of tube furnished with tentacular 

 cirrhi : a flabelliform abdominal appendage, and a very considera- 

 ble byssus ; mouth provided with double lips, beside two pairs of 

 labial appendages ; a single large retractile muscle apparent. 



Shell, Subcornate, fibrous, brittle, regular, equivalve, longi- 

 tudinal, triangular, pointed anteriorly, in which direction is the 

 summit, which is straight, wide, and frequently truncated poste- 

 riorly ; hinge dorsal, longitudinal, linear, toothless ; ligament occu- 

 pying nearly all the dorsal edge of the shell ; a single and very 

 wide muscular impression posteriorly ; a trace of the anterior in 

 the summit. Inhabits the Mediterranean sea. Fifteen species. 



Pinna rudis. Pinna flabellum. 



P. seminuda. P. angustina. 



P. nobilis. ' P. squamosa. 



P. marginata. P. muricata. 



P. pectinata. P. saccata. 



P. ingens. P. dolabrata. 



P. varicosa. P. vexillum. 



P. nigrina. 



FAMILY XVII. 

 Malleacea. Five genera. 



1. Genus Crenatula. 



Animal. Unknown. 



Shell. Irregular, much flattened, subrhomboidal, subequivalve, 

 gaping posteriorly ; summit anterior ; hinge longitudinal, dorsal, 

 toothless ; ligament submultiple, or inflated from place to place, 

 and inserted in a series of round cavities corresponding with the 

 dorsal edge; muscular impression unique and subcentral. Inha- 

 bits the Red sea. Seven species. 



Crenatula modiolaris. Crenatula bicostalis. 



