114 REPORTS ON INVESTIGATIONS AND PROJECTS. 



Prof. William K. Brooks studied the development of Salpa and 

 Doliolum, especially the asexual budding of these forms, and we 

 are informed that he obtained sufficient material to enable him to 

 complete his extensive memoir upon the subject, which has been 

 in preparation for some years. Salpse were exceedingly abundant 

 during April and May, but at the time of Professor Brooks's visit 

 they were relatively rare, and it is to be regretted that he was unable 

 to obtain a greater number of specimens. His assistant, Mr. Kellner, 

 made excellent drawings of all new or interesting forms. 



Preliminary Report of W. K. Brooks, on the Metamorphosis of 



Alpheus heterochetes. 



In 1881 Packard studied the metamorphosis of Alpheus heterochetes at Key 

 West, and showed that its development is much abridged and very slightly 

 different from that of A. minus and other species of the genus. At Key 

 West A. heterochetes lives within the tubes of sponges. 



In 1884 I found at Beaufort that the metamorphosis of this species is nearly 

 complete, and very different from that of A. minus. At Beaufort the species 

 is not parasitic. I had not then read Packard's paper, but as my other ob- 

 servations were made with care, and as ever} - stage of the development of the 

 larva was drawn, and as my results seemed to be irreconcilable with his, I 

 seemed forced to decide that he had made some mistake. 



In 1886 A. heterochetes was found in abundance in the Bahama Islands, liv- 

 ing as a parasite in the tubes of sponges. The larvae were studied and drawn 

 at every stage of their metamorphosis, which proved to be even more abridged 

 than that which Packard studied at Key West, and like that which is com- 

 mon to the genus as illustrated by that of A. minus and other common 

 species. 



These observations indicate that Packard's account was correct, and that 

 A. heterochetes has onp Ufa history at Beaufort, another at Key West, and 

 a third in the Bahamas; that the life history in the Bahamas is like that which 

 is characteristic of the genus ; the life history of Beaufort very different from 

 that of other species of Alpheus, and that at Key West midway between that 

 of the Beaufort specimens and that of the Bahama specimens. 



While our observations in the Bahamas thus indicate that Packard's ac- 

 count is correct, a verification of his observations at Key West is still to be 

 desired, and I was pleased to find larvae of A. heterochetes at the Carnegie 

 Laboratory in the Tortugas last summer, and to show that the life his- 

 tory of this species there, only a short distance from Key West, is as Pack- 

 ard describes it, and transitional between the life history at Beaufort and that 

 in the Bahamas. 



Prof. Edwin G. Conklin discovered that the substance of the egg 

 of the scyphomedusa Linerges is differentiated into concentric 

 layers in a manner comparable to the condition previously demon- 

 strated by him in mollusks and tunicates. The eggs of the highest 

 and of the lowest metazoans are therefore comparable even in their 





