24 EUCRATIID.E. 



not universally, developed at the side. Even on these, 

 however, they are not unfrequently intercalated amongst 

 the other cells. 



The branches are given off from the dorsal surface, 

 rising from about the middle of it; and the celts composing 

 them face in the opposite direction from those of the parent 

 shoot. It is evident that the ovicelligerous cell is in most 

 cases the first element of a branch, which is usually ap- 

 pressed to the shoot from which it rises, and united to it. 

 Occasionally, however, it remains free, and stands out 

 obliquely from it, showing clearly its real significance. It 

 should be remarked that in Eucratea also the ovicelli- 

 gerous cell occupies the position of a branch, and is in fact 

 the first element of one, modified for the discharge of a 

 special function. 



To a change, then, in the plan of the ramification may 

 be due the passage of the Eucratea-form into the Gemel- 

 laria-form. The branch which in the former genus is 

 given off in front originates in Scruparia at the back, and in 

 many cases becomes adnate to the shoot from which it rises ; 

 and we thus have as an occasional condition the form of 

 zoarium* which is universal and permanent in Gemellaria. 



The first cells of the colony are repent, as in Eucratea, 

 forming a series of greater or less length, adnate to the 

 surface on which the Polyzoon grows, from which the erect 

 shoots arise. 



SCRUPARIA CLAVATA, Hincks. 

 Plate III. figs. 5-8. 



SrRUPAiUA CLAVATA, Hincks, Quart. Journ. Micr. Sc. v. 175, pi. xvii. figs. 

 5-8. 



* EtsentioIJy the same form, but with this difference that in (icniparia 

 the cells arc subalteruate, while in Gemellaria they are eiactly opposite. 



