General llisturi/ oj the Marine Poli/zoa. 479 



Note on Iliantopora ferox, MacG., and 

 Cribriliiia inonoccros, Busk. 



In the earlier portion of this paper I have referred to Mr. 

 Kirkj)atrick's remarks on the systematic position of tlie former 

 of the above species, and have suf^gested that there is probably 

 a close affinity between it and Cribrilina monoceros. A careful 

 examination and comparison of the two forms has convinced me 

 that theyare very nearly related and should probably tiud a |)lace 

 in the same genus. Iveverting for a moment to Mr. Kirk- 

 Patrick's paper, I venture to suggest that the form which he 

 describes as a variety [intermedia) of Memhranipora radi- 

 cifera may prove to be only an early stage in the devehpment 

 of Iliantopora ferox. His figure certainly bears a very close 

 resemblance to cells of the latter species on the growing edge 

 of the colony which have lately come under my notice. The 

 zooecium represented in his figure is in an early stage of 

 growth ; the lower margin of the orifice is incomplete, but 

 from the base of the avicularian cell (or from the margin 

 beneath it) processes are budding which, in conjunction 

 probably with offshoots from the side-wall of the cell, have 

 already all but formed one or two of the large pores which 

 are so striking a feature of the species. A marginal cell in a 

 line colony of //. ferox (which Miss Jelly has kindly lent me 

 for examination) is in a similar stage of development, and 

 presents very much the same appearance. Other cells 

 exhibiting various phases of growth enable us to trace the 

 history of the mature form. 



As to the relationship between this species and G. mono- 

 ceros there can, I think, be little dilference of opinion. The 

 development of the zoacium is essentially the same in both. 

 In its earliest stages the cell is simply Membraniporiue in 

 character ; the first change is the completion of the calcareous 

 framework of the oritice, which is effected by the formation of 

 a bar across the aperture, which shuts off the upper portion 

 of it and constitutes the inferior margin of the oral opening. 

 By the successive growth of a number of calcareous processes 

 from the lower margin of the oritice and the side-walls of the 

 cell, the extremities of which meet and are fused together, 

 a perforated shield is formed which arches over and protects 

 the membranous front wall. As I have said, the method of 

 construction is similar in both forms, and the structural 

 elements are alike. They may certainly rai\)i in the same 

 genus, and probably in MacGillivray's Hiantopora. 



The affinity between these forms and the Cribrilinidaj is 

 sufficiently apparent, but they can hardly be included in the 



