140 SIDNEY F. HAEMBK. 



have escaped Smitt's attention. It must further be pointed 

 out that some of the exceptions to the rule which has been so 

 much insisted on above are probably due to the fact that some 

 of the formulae refer to C. aculeata^ as is admitted by Smitt 

 in two of the cases. 



A very interesting abnormality of C. eburnea is figured in 

 PI. XI, fig. 5. The internode in question was the penultimate 

 internode of a branch of a thoroughly characteristic colony, in 

 which no other abnormalities were detected. In addition to 

 bearing two lateral branches in a very unusual position, at its 

 upper end, this internode distinguished itself by producing 

 three zooecia arranged in a row along the middle of its front 

 surface, giving it, when seen from this side, an appearance very 

 much like an Entalophora, for instance. The back of this 

 internode appeared normal, and it was not obvious that any of 

 the three growing-points borne by the internode was constructed 

 in such a manner that it would have reproduced the abnormality 

 in the next following internodes. 



C. aculeata. Fig. 4. 



I believe this form, which is in many respects intermediate 

 between C. eburnea and C. ramosa, and which was originally 

 distinguished as a species by Hassall,^ to be a perfectly good 

 species. Nearly all recent authors have regarded it as a variety 

 of C. eburnea; this view is taken, for instance, by Hincks,' 

 Busk,^ Smitt,* &c. Even Johnston,^ although inserting it as 

 a distinct species, adds that he cannot persuade himself that it 

 is more than a variety of C. eburnea. 



My belief in the specific distinctness of C. aculeata rests 

 mainly on the characters of the ovicell; since a particular form 

 of ovicell (shown in fig. 4) is invariably found on colonies of 



1 Hassall, A. H., 'Ann. and Mag. of Nat. Hist./ vol. vi, 1841, p. 170. 



2 'Brit. Mar. Poljzoa,' p. 421. 



2 ' Cat. of Marine Polyzoa in Brit. Museum,' part iii, p. 4. 



* Loo. cit. 



» 'British Zoophytes,' ed. 2, p. 285. 



