518 MR. A. W. WATERS OX 



as ifc has been impossible to recognise it from Busk's figures the 

 name cleklostoma must stand. 



Loc. Queen Charlotte Island (Hincks) ; Japan, 100 fath. 

 (Ortmann). Wasin, Brit. East Africa, 10 fath. (520), collected by 

 Crossland. 



Petralia japonic a Busk. 



Lepralia japonica, Waters, Mar. Biol, of the Sudanese Red Sea, 

 Journ. Linn. Soc, Zool. vol. xxxi. p. 149, pi. xiii. figs. 10-12. 



Loc. Add (Natal, as Hemeschara gigantea Busk MSS. in the 

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

 Crossland. 



Petralia chuakensis, sp. n. (PI. LXX. figs. 10-14.) 



Specimens from Chuaka correspond in most particulars with 

 Busk's description of Leprcdia dorsiporosa *, but the notch at the 

 distal end of the zooecium is wanting, and in chuakensis the 

 proximal edge of the aperture is serrate. The aviculariura 

 at the side is curved and is larger than those figured by Busk. 

 The Zanzibar specimens have ovicells which are unknown in 

 dorsiporosa, and the wall, which is not much raised, is finely 

 perforated. 



The perforated area in the dorsal surface is for a broad radicle, 

 which, however, is not always developed ; a similar area occui"S in 

 Petralia vultur var. armata, and also in Petralia japonica there 

 is often a similar large radicle. Levinsen refers to the radicle 

 tube in P. dorsiporosa. There is a complete bar to the avicularia 

 often disappearing in Eau de Javelle preparations. There are 

 numerous uni- or few-pored rosette-plates scattered over the 

 distal wall. On the lateral wall, about halfway between the frontal 

 and basal walls, there is a row of about 5 few-pored rosette-pla.tes. 



There are about 28 tentacles. In the ovarium there are but 

 few ovarian cells. 



It has been thought best to give a specific name, although there 

 is much in common with P. dorsiporosa from the Torres Straits. 



Loc. Chuaka, Zanzibar, 3 fath. (502), collected by Crossland. 



Petralia vultur Hincks, var. armata, nov. (PI. LXX. 

 figs. 15-20). 



Type, Mucronella mdtnr Hincks, Ann. Mag. Nat. Hist. ser. 5, 

 vol.'x. p. 98, pi. viii. fig. 2 (1882). 



From Chuaka, Zanzibar, there are unilaminate specimens 

 difllering from the Mucronella vidtur as described by Miss 

 Thornelyt, in having a triangular mandible to the avicularium 

 attached to the mucro. There are also a large number of raised 

 round avicularia, with semicircular mandibles, and a distinct 

 ci'oss-bar. These avicularia are sometimes on the top of a raised 



* Zool. Chall. Exp. vol. x. p. 143, pi. xviii. fi°;. 4. 



t Ceylon Peavl-Oyster Fisheries, vol. iv. p. 124 (1905). 



