.LEPA. 71 



A. With tne valves connected by a cartilage, and at* 

 tached to ajlesky stalk. Barnacle, 1 tp 7- 



B. Firmly fi^ea, without stalk, conical, icith an inter- 

 nal lid. Acorn-shell, 8 to 20. 



1. Lepas anatifera. Duck Barnacle. 

 Pennant, -pi. 41, upper figures Da Costa, pi. 17- f. 3 

 Donovan, pi. 7JVood, pi. 1 1 Dorset Cat. pi. 2. f. 3. 



Shell flattish, with five blueish valves connected by a 

 yellow membrane ; the two lower-ones large, somewhat 

 triangular, slightly wrinkled longitudinally, and obscurely 

 striate in a radiate manner from the lower angle on the 

 anterior side ; the two top ones not half the size, long and 

 tapering down to a rather obtuse point, angular on each 

 side towards the upper part, and longitudinally striate; 

 the back-valve long, narrow, rounded on the back, tapering 

 towards the ends, curved, striate longitudinally, and ter- 

 minating towards the bottom in a kind of ridge : stalk long, 

 transparent, horn-color, growing darker and more opake 

 ^and wrinkled towards the shell, rarely red : length above 

 an inch and a half; breadth an inch. 



Variety A. The back valve appearing as if separated into 

 jsevcral distinct joints. 



Variety B. The back valve strongly ribbed longitudi- 

 nally at the sides on the lower part, and the ribs closely 

 tubercled. 



Variety Q. The back valve, with a longitudinal row of 

 obtuse tubercular denticles. 



Lister, pi. 439. f. 282, left hand figure. 

 Variety D. The back valve deeply and sharply serrated. 

 Fig. 22. 



Lepas dentata. JVood, p. 67 Dittwyn, p. 32. , 

 Theseseveral varieties presented themselves to us among 

 the vast mass which floated into the river Ex, in Devon- 

 shire, in the summer of 1817. And as the other parts of 

 the shell and its appendages were in every respect similar 

 to L. anatifera, we cannot consider any of them as entitled 

 to specific distinction. 



On drifted timber, and the bottoms of ships, 



2. Lepas 



