HTDROIDS FROM WOOd's HOLL, MASS. 351 



first blastolyte was seen free^ tiie second one came off from the 

 polyp and^ shortening somewhat, became arched (fig. 5, a), and 

 as it was before thickened in the middle, the two ends ap- 

 proached more and more, and formed the foot end of the 

 polyp. Even the next day the forked foot of this little animal 

 could be plainly seen (fig. 5, b). Here, then, the anterior or 

 oral end had formed from the side of the parent. On the next 

 day I saw the same result accomplished in another way (figs. 

 7 — 9). A constricting segment was found at the end of the 

 nearly severed parent, and it had a large hump on one side. 

 This lateral protuberance became larger as the constriction 

 proceeded, then it grew still more at the expense of the foot end, 

 being now severed from the parent ; it became the greater bulk, 

 and the former foot-mass became a narrow process (fig. 9, b'). 

 The constricted end was also gradually drawn in until the 

 whole assumed the shape of the ordinary blastolyte (9, b"). 

 Here again the oral end of the blastolyte was formed from the 

 side of the parent polyp, and as a lateral outgrowth.^ 



The normal process of asexual reproduction of Hypolytus 

 is different from any of the cases of fission described among 

 hydroids. Comparison with strobilation as it occurs among 

 the Scyphozoa, as furnishing a parallel case among the 

 Hydrozoa, seems too strained, especially since it is at the 

 wrong pole, and the resulting products are different.^ It is 

 different from the frustulation ofSchizocladium ramosum 

 described by Allraan,^ since there fission takes place at what 

 would be the oral end. 



The sacculse of Schaudinn's Halermita represent freed lateral 

 buds, and resemble the blastolytes of Hypolytus only in that 



* Not thinking of tlie possible significance of these phenomena, no attention 

 was paid to the relative time it took such a blastolyte to produce tentacles, 

 and it is reserved for future observation to see if the explanation given on 

 another page will be borne out. 



^ The well-known phenomenon of "decapitation" among hydroids does not 

 come into consideration here, since it is not a process of reproduction. 



^ AUman, G. J., * A Monograph of Gymnoblastic or Tubularian Hydroids,' 

 1871-2. 



