4 PROCEEDINGS OF THE NATIONAL, MUSEUM. vol. 04. 



the tips of tJtie exopodites of the first and second maxillipeds. The 

 larva is 1.3 mm. long and 0.5 mm. through the carapace (figs. 1 and 2). 



SECOND ZOEA. 



The second zoea is distinguished most readily from the first by 

 the presence of six swimming hairs on the maxillipeds (figs. 4, 14, 

 and 16). The length of the larva is now 1.6 mm. and its width 0.6 

 mm. The increase in size is largely in the cephalothorax (figs. 3 

 and 4). The maxillule (fig. 10) bears an epipodital hair. The epi- 

 podital process of the maxilla has begun its transformation and is 

 now tripartite (fig. 12). On the abdomen the telson alone is slightly 

 changed. Its median tooth is relatively larger (fig. 18). 



PINNOTHERES HOLOTHURIAE Semper. 



The description of this zoea here given is from Semper who gives 

 a figure (fig. 48) and a very brief note in his book. 



The first zoea resembles that of P. ostreum very closely indeed. 

 There is not even a vestige of any of the spines of the carapace. 

 The only other distinction between the two species is the absence 

 of certain pigment spots in P. Tiolothuriae. As Senfper's figure was 

 published in 1881 it is possible that he did not record all of the pigment 

 spots. 



PINNOTHERES PISUM Latreille. 



This was the first of the Pinnotherid larvae to be described. 

 Thompson has an interesting paper on the natural history of peacrabs 

 and gives two figures and a few meagre notes on the larvae. 



The dorsal spine of the carapace is wanting but the rostral and 

 lateral spines are well developed (figs. 49 and 50). This peculiar 

 condition is vouched for by Bell. As far as can be determined from 

 Thompson's rude figures, the appendages offer no peculiarities. The 

 abdomen expands into a flattened plate posteriorly as in P. ostreum. 

 The telson resembles that of P. ostreum closely. Its distal border is 

 produced into three deltoid teeth between which lie three spines on 

 each side. 



PINNOTHERES VETERUM Bosc. 



The zoeas of this form as well as of a Pinnotheres taken from 

 Ascidia mentula were hatched by Gourret. No description was given 

 and only one figure, that of the telson (fig. 51). The abdomen is 

 only slightly broadened as is the telson also. The three teeth are 

 longer and narrower than in P. ostreum and are more like the cornua 

 of other brachyuran telsons. 



PINNOTHERES MACULATUS Say. 



This form is common in the tow at Beaufort, occurring throughout 

 the summer. It is strikingly different from the other known larvae 

 of Pinnotheres and would hardly be referred to the genus unless 



