530 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



long', and they were often taken at the surface until 8 to 12 mm in length, 

 the larger ones being taken in the first part of September. 



The young of Virbius zostericola appear at about the same time as 

 those of Palcvmonetes, or a very little later, and pass through quite simi- 

 lar changes, The young attain the adult form when not more than 3™**- 

 in length, and were frequently taken at the surface, both in the day- 

 time and the evening, until they were 10 mm long, those 8 to 10 mm long 

 being common in late August and early September. 



The larval forms of several other Macrourans were taken at different 

 times, but none of these were abundant, and I have not been able to 

 connect them with the adult forms of any of the common species of the 

 New England coast. 



The young of Gebia affinis, only 4 mm long, but with nearly the form of 

 the adult, was taken at the surface on the evening of September 3. 

 The young of Callianassa Stimpsoni, about 4 mm long and with nearly all 

 the adult characters, was also taken at the surface early in September. 



The hermit-crabs (species of Eupagums) when first hatched have much 

 resemblance to the young of shrimp at the same period, and have simi- 

 lar habits. The young of one of the species, after it has passed through 

 the earlier stages, and when it is about 3 mm long, and has all the 

 cephalothoracic appendages similar to those of the adult, has still a 

 symmetrical abdomen, like that of a shrimp, with long swimming-legs 

 upon the second, third, fourth, and fifth segments, and broad laminated 

 appendages upon the penultimate segment. Young, in this and the 

 earlier stages, were common at the surface in Vineyard Sound during 

 the last of August and the first of September. 



Sippa talpoida probably passes through a metamorphosis similar to 

 that of the hermit-crabs. The young attain nearly the adult form before 

 they are more than 5 or 6 mm long, and specimens of this size were 

 taken at the surface in Vineyard Sound on the evening of September 3. 

 I have also found, early in September, the young a little larger 

 upon the outer shores of Fire Island Beach, where they were left 

 in large numbers by a high tide, and soon buried themselves in the 

 sand. 



All, or at least nearly all, the species of Brachyura living on the coast 

 of New England pass through very complete and remarkable meta- 

 morphoses. The most distinct stages through which they pass were 

 long ago described as two groups of crustaceans, far removed from the 

 adult forms of which they were the young. The names zoea aud meg. 

 aiops, originally applied to these groups, are conveniently retained for 

 the two best marked stages in the development of the crabs. 



The young of the common crab, (Cancer irroratus,) in the earlier or 

 zoea stage, when first batched from the egg, are somewhat like the form 

 figured on Plate VIII, (fig. 37, the latest stage of the zoea of Cancer 

 irr or atus, just before it changes to the megalops,) but the spines upon 

 the carapas are all much longer in proportion, and there are no signs of 



