194 ZOOPHYTES. 



embarrassing. But numerous observations prove the discrepant structure 

 of the young and the adults, and even between the adults of the same 

 species of many Sertularise. This is possibly shown under various modi- 

 fications throughout the whole race. Only a single cell could be disco- 

 vered resembling the cells of the adult ; but tlws, together with the articu- 

 lations of the stem of the originating, or of early specimens, established 

 the identity, although there was no reason to doubt the correctness of 

 experiments and observations. The cells were very transparent. — 

 Plate XXXVIII. figs. 8, 9, 10. 



The sphere is imperfect, in as far as being then open ; were it per- 

 manently complete, the orifice would be obstructed. 



On different occasions, both simple and compound vesicles have oc- 

 curred on the same specimen. 



A corpusculum, white or yellow, resembling those in the sphere, 

 sometimes appears on the summit of the pedestal sustaining it. 



One or two globular or somewhat elongated corpuscula, probably 

 planulse, are seen in the ampuUate vesicles. 



Besides these, yellow corpuscula have been also observed in the spi- 

 nous vesicle above mentioned, but under certain irregularities. Of five or 

 six on a branch, the first contained a large whitish corpusculum, the second 

 a pale yellow one, the third two more vivid, the fourth had three like 

 them. The fifth vesicle was crowned by an irregular transparent vessel, 

 with a yellow corpusculum at the bottom, as if seated on an internal stalk 

 rising up through the vesicle. Another portion of the lower branch bore 

 nine spinous vesicles with still greater irregularities. Here a conical ve- 

 sicle, or a long bladder with contents similar to the yellow globules, of the 

 wonted sphere, supplanted it. 



These varieties or anomalies are of difiicult description to become in- 

 telligible. 



When the great accumulation of above 2000 planulse was verging to 

 decay, and the whole water emptied on April 18, more than 100 spines 

 indicating nascent Sertulariaj were exposed on replenishing the vessel. 



Vegetation. — The origin and increment of organic bodies, always deeply 

 interesting to the contemplative, though advancing in strict accordance 



