5i6 THE AMERICAN XATURAIJSr. [\'.>i.. XXWIII. 



These phenomena stn.n-ly su--est an excretory activity, and 

 this suo-o-cstion is strengthened by our knowled-e of the behavicr 

 of amitotically divicHng nuclei m other animals, but especially by 

 the results of R. W. Hoffmann on the behavior of the nuclei and 

 nucleoli in the large macromeres of the embryos of Nassa muta- 

 bilis. Complete proof, however, that the activities described in 

 the sub-velar masses of Fasciolaria are really the exhibition of an 

 excretory process, is found in a chemical analysis of an aqueous 

 extract of these bodies. Such an extract analyzes like a dilute 



Double Reproduction in the Medusa Hybocodon prolifer : H. 

 F. Perkins, University of \'ermont.— Hybocodon is familiar to 

 American biologists as a singularly asymmetrical jelly-fish found 

 along our coast in the early spring. Of the four radial canals 

 only one is continued beyond the bell in a tentacle. 



The method by which this medusa has been described as 

 reproducing its kind is by developing, upon the bulbous base 

 of this solitary tentacle, gemmiferous buds. These, when 

 mature, become detached from the parent and swim away as 

 free jelly-fish. Only the one tentacle is developed upon these 

 buds, and at the time of liberation the base of this tentacle 

 frequently carries maturing buds of a second generation. 



While this is a rapid and efficient means of propagation, it is 

 not the only one. In addition to this asexual process, a sexual 

 process is also present. Eggs or sperms are produced within 

 the gonads which surround the manubrium, and these develop 

 within the tissue to the condition of tentacled actinula larvse. 

 Thus the adult Medusae give origin to two sorts of offspring, 

 one by gemmation, the other by sexual production of viviparous 

 young. This in itself is not anything extraordinary, but it is a 

 matter of interest that the two processes are found taking place 

 •simultaneously in the same individual, and that this coincidence 

 does not lessen the rapidity with which the embryo jelly-fish are 

 produced on the tentacle bulb. The fact is of interest only as 

 showing that the reproductive activities of Medusae are even 

 more unrestricted than we have realized. 



The sexually produced larvae of Hybocodon mature upon the 



