300 



The colonies hifurcakMl, with lairiy broad, compressed, Iwo-layered branches. 

 Two colonies lioni \'ictoria. 



Hasiv. nuriciihtta Bnsk ' which lliis anlhor willi some iiesifation lel'eis to the 

 genus Hasiiicllia, doubtless belongs to tiiis genus and is most nearly rehilcd to lUisiv. 

 (lustraliensis. As in this species the bridge dividing the suboral ojjening from the 

 secondary aperture is provided with two small avicularia (PI. XIX, (ig. 17 a). I 

 have examined a fragment from the Challenger station 13') c. 



Gephyrophora polymorpha Busk. 

 Gephyrophora polyniorj)ha Husk, Challenger, Zoology, Vol. X, Part I, p. 1(57, 



PI. XXXIV, fig. 2. 

 Schizoporella polymorpha Waters, Challenger, Zoology, Vol. XXXI, Pari III, 



p. 29, PI. II, figs. 21—24. 



The zocecia, usually tongue- or lyre-shaj)ed, are fairly strongly arched, sepa- 

 rated by distinct sutural furrows and provided with fairly densely placed, short 

 pore-canals with a large inner opening. The well-chitinized operculum which is 

 provided with two muscular dots is of an oval outline and the small accessorial 

 part has a rounded poster, which is separated from the anter by a not very sharp 

 bend on each side. The hinge-teeth are well-developed. The two lateral halves of 

 the low, ring- or wall-shaped peristome are connected with each other by a strongly 

 projecting, compressed arch, formed by the coalescence of two originally distinct 

 processes, each bearing a large avicularium. Its central pari which separates the 

 j)oints of the two avicularia has in most zod'cia the form of a large, projecting, 

 cjuadrangular plate. The perforation lying between the bridge and the proximal 

 part of the aperture corresponds to the peristomial pore in Hasivellia and as in 

 the sjjecies of that genus is much larger in the ordinary zoa>cia than in those 

 bearing oa'cia. The distal wall and the lateral walls, which are thin, are provided 

 with a large number of scattered, uniporous rosette-plates. 



The ooecia, which are present in very large number, have when seen from 

 the surface of the colony a similar appearance as in tlu' two species described 

 above, appearing as large, indistinctly marked olT swellings which are either pro- 

 vided with pores over their whole surface or do not have these on a median part. 

 They are however considerably more elongated than in the species of the genus 

 Hasivellia and in fact have quite a different structure. Thus, as Waters has 

 shown, their zoa>cial half is immersed into the cavity of the zocecium itself. They 

 have an unusually elongated form for otvcia and a thick cryptocyst layer is 



' 8, p. 173. 



