fi% Dr. Baird on the genus Cypridina, 



derable difficulty I succeeded in dissecting it. For the accom- 

 panying sketches of this species I am indebted to the pencil of 

 Mr. Charles Ager. 



The eyes I did not succeed in making out. The first pair of 

 antennae (PI. VI. fig. 3) are large and pediform : they consist 

 each of four articulations. The first or basilar joint is stout and 

 of a considerable size ; the second is nearly equally large j the 

 third is short, about half the size, and the last is more slender and 

 terminated by several strong setse. From the junction of the 

 third and fourth joints issues a bundle of long slender setse as in 

 CypriSj and the second articulation is beset on both upper and 

 under edge with numerous strong setse also. The organ which he 

 calls the natatory foot (fig. 4) is however a very remarkable one : it 

 consists of a very large, fleshy, round basilar joint, from which 

 issue two branches separate from each other and differing in size 

 and structure. The superior is much the larger of the two, and 

 consists of one long and stout joint and six short ones, from the 

 base of each of which issues a long hair. The inferior branch is 

 much smaller and consists of two nearly equal joints, the lower ter- 

 minating in two short claws. According to the figure given by 

 M. Edwards, this pair of feet consists of only one branch instead 

 of two. The mandible I did not succeed in seeing ; but the first 

 pair of jaws appeared to be very like that organ as represented 

 by M. Edwards. The second pair of antennse presented the ap- 

 pearance given in fig. 5, but the parts were too rigid to enable me 

 to describe it distinctly. On the posterior portion of the animal 

 there was another organ, which is described by M. Edwards in the 

 Cypridina as a slender, cylindrical, filiform and twisted body 

 which supports the ova. In this species it appeared a cylindrical 

 body (fig. 6) composed of a very great number of small joints, of 

 a twisted form, and giving off from each side several pretty long 

 setse which appear numerously jointed also and furnished at their 

 extremities with sharp spines. It resembles more the same organ 

 as described in the Asterope by Philippi than that in the Cypri- 

 dina of Edwards. The abdomen is terminated by a double caudal 

 plate (PI. VI. fig. 7), broad, flat, and armed with nine spines ; six 

 of which are very strong and serrated on their under edge. The 

 first is the longest and they gradually become shorter as they 

 descend, the three last being much smaller than the others, not 

 serrated on their under edges, but furnished with a tuft of short 

 setse at their extremities. This caudal plate appears to be a simple 

 continuance of the abdomen, and not articulated with it as in the 

 tail of Cypridina figured by M. Edwards, and in this particular 

 resembles much more nearly that organ as represented by Phi- 

 lippi in his Asterope. 



Sp. 2nd. Cypridina Adamsi. PI. VII. fig. I. Shell of the size 



