No. i.] MORPHOLOGY OF THE ACTINOZOA. 141 



been able to study some very similar larvae, and has shown that 

 Semper's suggestion as to their relationships was correct. He 

 gives a detailed account of a form closely similar to Semper's 

 larva, differing from it only in the ciliated band being relatively 

 shorter, and in the absence of a posterior opening, and shows 

 that it possesses twelve mesenteries arranged in the same man- 

 ner as the five dorsal pairs and the ventral directives of the 

 Zoantheae ; that is to say, it possesses a pair of perfect ventral 

 directives, a pair of imperfect dorsal directives, and between these, 

 two pairs, on either side, each pair consisting of a dorsal perfect 

 and a ventral imperfect mesentery. There seem to be no good 

 reasons for doubting that this form is the larval stage of a Zoan- 

 thid, even though no specimens were found showing the place 

 of origin of the seventh, eighth, etc., pairs of mesenteries. 



Van Beneden also announces that he has specimens agreeing 

 closely with the forms described by Semper as possessing a 

 circular band of cilia, but defers a detailed description of them 

 until a future occasion, merely stating that they belong to the 

 same Actinozoan group as do the larvae with the longitudinal 

 band. 



I have had in my possession for several years some Actino- 

 zoan larvae collected by the aid of the surface net at Beaufort, 

 North Carolina, during the location there of the Marine Labor- 

 atory established by the Johns Hopkins University. They 

 resemble the second of Semper's larvae in the possession of a 

 strong ring of cilia encircling the body, and, as will be seen from 

 the following account, are without doubt larvae of a Zoanthid. I 

 cannot say of what species they are the young, as no Zoanthid is 

 known to occur at Beaufort. Epizoanthits Americanus, Verr., 

 has been dredged in 65 to 263 fathoms off the coast of North 

 Carolina, but it seems improbable that the larvae belong to this 

 species, since they are constructed, as will be seen, upon the 

 microtype, whereas EpizoantJuis follows the macrotypal plan. 



Four of the five specimens I possess are in the twelve-mesen- 

 teried stage, but the fifth is much older, possessing mesenteries 

 of the ventral group, and being evidently ready to settle. I 

 shall give a detailed description of the characters of these larvae, 

 inasmuch as they serve to confirm the results, as to the affini- 

 ties of the Zoantheae, arrived at from anatomical studies. 



The younger ones are somewhat pyriform in shape, and have 



