THE FIRST ZOEA OF PORCELLANA.. By W K. 



BROOKS and E. B. WILSON. With Plates YI and VII. 



Since 1835, when Thompson obtained the larva of a British 

 species of Porcellana from the egg, this very remarkable zoea has 

 frequently attracted the attention of naturalists, and we now have 

 quite an extensive list of papers, giving a satisfactory account of the 

 structure of the advanced zoea, and of its transformation into the 

 adult crab. The bibliography of the subject is given, at length, 

 in a recent paper by Faxon, (On some young stages in the devel- 

 opment of Hippa, Porcellana and Pinnixa. Bulletin of the 

 Museum of Comparative Zoology, at Harvard College, Vol. V, No. 

 11,) and it seems unnecessary to duplicate it here. 



Most of the observers who have studied it started with the ad- 

 vanced zoea, which is frequently captured with the hand net at the 

 surface of the ocean, and the few papers which notice the early 

 stages of the larva were published so long ago, that a minute 

 account of the young, as it leaves the egg, is still lacking. 



During the latter part of June, 1880, we obtained, at the marine 

 laboratory of the Johns Hopkins University, at Beaufort, N. C., 

 a female specimen of Porcellana ocellata, Gibbes, with eggs, which 

 we succeeded in keeping alive, and in good condition until the 

 eggs hatched, and we were thus supplied with an abundance of 

 material for studying the early stages. 



As all the members of the party were at the time fully occupied 

 with other work, we undertook to study the larva together, and 

 to make as many notes and drawings of the early stages as 

 possible. 



This paper is therefore the result of our combined observations, 

 but the work of copying the original drawings, and of preparing 

 the description has been done by W. K. Brooks. In the explana- 

 tion of the figures the author of the drawing which was copied is 

 named in each case, although in nearly every case, the accuracy of 

 the observation was verified by a independent drawing by the 

 other observer. 

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