On Megalocypris princeps. 



moderately tumid, and of a rather regular oval fusiform 

 shape, with the side-contours quite evenly curved and both 

 extremities narrowly produced. The greatest width, which 

 occurs in the middle, does not fully equal the height of the shell. 



The valves are very nearly equal, very thin and 

 pellucid, so as to allow the body of the animal with its 

 appendages to be faintly traced through it. Anteriorly they 

 are encircled by a very narrow, hyaline rim, and a similar 

 rim may also be observed on the inferior part of the 

 posterior extremity. The inner duplicatures are of mode- 

 rate size and not very sharply defined, that of the anterior 

 extremity being, as usual, the broader, and exhibiting a very 

 delicate longitudinal striation. 



The surface of the shell is perfectly smooth and glossy, 

 without any obvious sculpturing, except the usual pits, 

 which are rather small and distant. It is clothed anteriorly 

 and posteriorly with very short hairs, densely crowded toge- 

 ther, which gradually disappear on the dorsal and median 

 parts of the shell. In the centre of each valve, a little in 

 front of the middle, the usual muscular pits, indicating the 

 insertion of the great adductor muscle of the shell, may 

 be traced. Their arrangement is that usually found in 

 Oyprididæ. 



The colour of the shell in the preserved specimens is 

 light yellowish green, semipellucid, with a few scattered, 

 darker green shadows, partly in the middle, partly along 

 the edges. 



The enclosed animal is built, on the whole, upon the 

 same type as in other Cypridids, as shown by fig. 4, 

 which exhibits the animal of a male specimen in its natural 

 attitude, lying within the left valve, the right one being re- 

 moved. The body is attached to the shell throughout the 



