522 MR. A. W. WATERS ON 



beyond the zoarium. Sometimes they start from the base, and 

 the poiypides stand out from the upper surface of the zoarium, 

 A similar case fi-om the Red Sea is mentioned in the addenda to 

 my Report*. Probably the hydroids in both are Clava. 



There are about 18 tentacles. There are a great number of 

 ovaria with two small ovarian cells, and in only one or two xBases 

 has a moderate-sized ovarian cell been seen, and the ovaria are of 

 the Bugula, type. The ovaria may be surrounded by testes. 



Log. Bass's Straits, 38 fath. (Chall.) ; Port Phillip Heads 

 (MacG.) ; Port Jackson. N.S.W. ( Waters) ; Sagamibai, Japan 

 (Oh.) ; Manaar, 34 fath. ; Ceylon Coast, 32-34 fath. ; off Port 

 Blair, 100 fath.; St. 59, 32 fath., St. 77, 35 fath. {Thornely). 

 Wasin, Brit. East Africa, 10 fath. (501), collected by Crossland. 



HOLOPORELLA APERTA Hincks. 



Waters, "Mar. Biol, of the Sudanese Red Sea," "Bryozoa," 

 Journ. Linn. Soc, Zool. vol. xxxi, p. 161, pi. xviii. figs. 20-23 

 (1909). 



Log. Additional. Wasin, Brit. East Africa, 10 fath. (500) ; Ras 

 Osowamembe, Zanzibar Channel, 10 fath. (504), collected by 

 Crossland. 



HoLOPORELLA ALBIROSTRIS Smitt. (PI. LXXIII. fig. 11.) 



Celle'pora alhirostris, forma tyinca Smitt, " Floridan Bryozoa," 

 pt. ii. p. 70, pi. xii. figs. 234-239 (1873). 



Cellepora alhirostris Busk, Journ. Linn. Soc, Zool. vol. xv. p. 347, 

 pi. xxvi. fig, 2 {no7i fig. 1) (1881) ; Zool, Chall. Exp. vol. x. pt. xxx. 

 p. 193, pi, xxxiv. fig. 7, pi. XXXV. fig. 3 (1884) ; Waters, Quart. 

 Journ. Geol. Soc. vol. xli. p. 304 (1885); op. cit. vol. xliii. p. 68 

 (1887); Ann, Mag, Nat. Hist. ser. 5, vol. xx. p. 197(1887); 

 MacGrillivray, Prod. Zool. Yict. dec. xvii. p. 249, pi. 167. fig. 1 

 (1888) ; Mon. Tert. Poly. p. 109, pi. xiv. fig. 11 (1895) ; Tliornely, 

 "Mar. Poly. Indian Ocean," Trans. Linn. Soc, Zool. ser. 2, vol, xv. 

 pt. 1, p. 155 (1912). 



In //. alhirostris there is great variation in the colour, some 

 being very dark with the ends of the rostra white, others may be 

 nearly white. 



There are vicarious duck-bill avicularia and the border of the 

 rostral avicularia is denticulate ; the oral glands (fig. 11) are very 

 long, and there are 16-17 tentacles. 



A specimen is partly adnate, from which bilaminate branches 

 arise. The unilaminate portions, when seen from below, are quite 

 regular with the sides of the zooecia parallel, as in so many 

 Schizoporellida3. 



Both Smitt and Busk expressed doubt as to whether H. alhi- 

 rostris and H. hispinata were synonyms, but this is not the case, 

 for alhirostris has a long spine below the oral aperture, while 

 hispinata has a short avicularium ; further, in H. alhirostris there 



* Journ. Linn. Soc, Zool. vol. xxxi. p. 254, p. 163, pi. xv. fig. 16 (1910). 



