200 



Pedunculated. Supported by a moveable, coriaceous, 

 tubular peduncle, attached by its base to marine bodies. 



1. Anatifa. A pedunculated, five-valved shell ; the 

 valves unequal, pressed together so as to be nearly conti- 

 guous ; the lowest on the sides being the largest. Recent. 

 PL viii. fig. 28. 



2. Pollicipes. A pedunculated shell, formed of thirteen 

 or more subcontiguous, unequal valves ; the lowest at the 

 sides, being the smallest. Recent. 



Lepas scalpellum, Lin. ; Lepas mitella, Lin. ; Lepas 

 pollicipes, Gmelin. 



3. Cineras. Leach. 



A pedunculated shell, with five oblong separate valves, 

 not entirely covering the body ; two at the sides of the 

 opening, the others dorsal. Recent. 



Lepas coriacea. Pallas. 



4. Otion. A pedunculated shell, with two separate 

 small semilunar testaceous valves adhering near its lateral 

 aperture. Recent. 



Lepas aurita. Lin. 



Trigonellites. A slightly rounded, trigonal, thick shell, 

 gaping on each gide. The inferior margin nearly on a 

 straight line ; the anterior and superior margins in a gently 

 waving line. The outer surface of each valve pierced by 

 numerous foramina, which, passing nearly through its sub- 

 stance, give it the cancellous appearance of bone ; the in- 

 ner surface smooth, but marked with striae, agreeing, in 

 their direction, with the posterior and anterior margin. 

 The assumed hinge completely linear, without teeth ; there 

 being only, on the posterior margin of each valve, an appro- 

 priate, linear surface for the attachment of cartilage or liga- 

 ment externally. There is no appearance of muscular 

 attachment. PI. viii. fig. 29. 



