[52] MR. JAMES RITCHIE OX IIYDROIDS i^^'^}' 28, 



all along tbe walls, pushing the endoderm iuwai-ds until it pro- 

 trudes into the hollow of the gonophore. The male gonophores 

 are similar in origin and shape to the female, Iwt are in general 

 considerabl}- longer. lu no case could a spadix be distingui.'ihed. 



The structure of the gonophore above described is of tbe 

 simplest type. It appe'ns to be merely a blind branch of the 

 genei-al ccenosarc of the colour within the walls of which ova 

 develop. 



A.ssociated with the specimens were several creeping Hydroids, 

 Filellum serj)e)is, Cuspidella himulis, Camjxinularia mittahilis, and 

 an endoproctan polyzoon (C'lioriella ?). 



Localities, (a) St. Vincent, Cape Verde Islands : gi-owing 

 on the bottom of a lighter, 20th and 30th July, 1904.— 

 (6) Dredged ; Boa Vista, Cape Verde Island.s, August ? 1904. 



Family B o u G a i s v i L L 1 1 D .e. 



Hydractixia VERDI, sp. n. (Plate XXIII. figs. 6 & 7.) 



Among dredgings taken at Porto Gi-ande four /"HSi/s-like gas- 

 teropod shells were obtained overspread by Hj'dractinia colonits. 

 The nutritive hydranths, which grow in the giooves of the shell- 

 sculptuie, are in vaiious stages of contraction, the longest 5 mm., 

 the shortest with th^ir ring of tentacles almost resting on the 

 surface of the shell. The tentacles are short, set in two almost 

 indistiuguishalile whorls, and vary in number from 9 to 12, 

 9 being perhaps most frequent. The hypostome is club-shajied. 

 No spiral filaments are present, although along the margin of the 

 shell there occur elongated polj'ps with insignificant tentacles. 

 Short chitinous spines, about 0-3 mm. long, with jagged edges, 

 occm" throughout the colony, being arianged for the most part 

 upon the ridges of the shell. The bla.stostyles are somewhat 

 smaller than the nutiitive hydranths, being about 1 mm. in height, 

 but unlike those of H. echhiata thej- bear well-developed tentacles 

 eight or nine in number. The basal rhizom expan.siou is thin. 



Gonosome. — The reproductive bodies are fixed gonophores 

 arising from the body of the blastostjle some distance below the 

 tentacles. They occur in a single whorl containing three or four 

 individuals and are borne on short peduncles. In the specimens 

 examined the gonophoi-es w"ere all female, containing thi-ee large 

 ova ; while in the more mature examples these were sepaiated 

 towards the exterior by pigmented bauds running from the base 

 towards the summit of the gonophore — branches of the spadix. 



This species is closely lelated to II. pacifica described from 

 Calbuco b}' Hartlaub (190.5, p. 519), but that species diflers in 

 possessing about 15 tentacles on the nutritive hydranths, only 

 5 or G on the blastostyles ; in lacking spines on the basal expan- 

 sion ; in bearing only one ovum in each gonophore. 



LoaaliUj. Porto Grande, St. Vincent, Cape Verde Islands; 10 

 fathoms. 

 498 



