350 L. MURBACH. 



soon as free, and apparently dissolves the portion of the peri- 

 sarcal tube immediately above. In specimens kept in glass dishes 

 the whole process of fission took place in about six hours. The 

 blastolytes given oflF by specimens in confinement did not show 

 much disposition to move about, as did one found free in some 

 tow. After rising up on the pointed end the tentacles begin 

 to bud out on the enlarged upper end as minute knobs (figs. 5, 

 6), generally two oral ones first, then two aboral, and almost 

 simultaneously with the two aboral ones the second pair of 

 oral tentacles develops. 



When about 2 mm. in length the mouth opening is present 

 and the nematocyst collar begins to show. There are five oral 

 and nine aboral tentacles, all somewhat knobbed. The odd 

 number of tentacles shows that after the first two they do not 

 continue to develop in pairs. At this stage the foot end rests 

 curved like in adults, a character which is also evinced by the 

 larvae of other hydroids. The perisarcal tube is present, being 

 fully developed up to the collar. The tentacles are solid at a 

 very early stage. 



When several blastolytes are given off in succession, a group 

 of polyps may arise, and remain close together for some time. 

 So situated, debris collects on the remnants of the perisarc, 

 and the individuals seem to stick in the accumulated mass. 

 The parent meanwhile has moved a considerable distance from 

 its offspring. 



This is a brief account of the normal process of asexual re- 

 production as it takes place in the larger number of cases ; but 

 in some, such a pronounced modification was observed as to 

 warrant a separate description. 



In the first case noticed (fig. 4) the constricting mass, the 

 second of two starting out apparently normally, began to show 

 a decided lateral thickening, evidently an accumulation of 

 material for some future use. The first blastolyte continued 

 its normal development, while the enlargement on the second 

 one increased, evidently at the expense of the two ends, for 

 which their attenuation speaks (fig. 4, a). At this point my notes 

 read : — After 9.20 a.m., or about two and a half hours after the 



