28 THE VOYAGE OF H.M.S. CHALLENGER. 



No doubt, now that our attention is called to these bodies, we shall find them in many 

 other cases, though I have looked through many preparations showing the organic struc- 

 ture without detecting them. 



Porella proboscidea, Hincks, seems closely related, but differs in having the oral 

 avicularium prolonged in a tubular manner. 



Lepralia lonchaea, Busk. 



Lepralia lanchxa, Busk, Zool. Chall. Exp., part xxx. p. 146, woodcut, fig. 43. 



The specimen in the British Museum has ovicells, which are large, somewhat decum- 

 bent, and the lower border of' the peristome encloses a sort of shelf Avicularia placed 

 diagonally on the side of the peristome. The general character and the ovicell would 

 indicate that it is the same as Lepralia vestita of Hincks, from Tahiti ; but there seems 

 to be a difference in the operculum, which prevents my uniting them without a more 

 complete examination. 



Lepralia castanea, Busk (PI. III. figs. 36, 37). 



Macronella castanea, Busk, Zool. Chall. Exp., part xxx. p. 157, pi. xix. fig. 6. 



In most specimens the projection of the lower border of the oral aperture is not as 

 distinct as shown in Mr. Busk's figure. A lip of this kind occurs in several cases 

 in Lepralia, and the operculum indicates that it should be placed with Lepralia. 

 Mucronella is a genus which in my opinion should be abolished, and species have been 

 placed under it with a distinct mucro, with an avicularian chamber, with a lip, or with 

 an internal denticle, as Smittia delicatula. Some seem to belong to Lepralia, most to 

 Smittia, but even if the genus Mucronella be retained this could not be placed there. 

 Specimens from Station 122, 350 fathoms, have one or more large dorsal pores, from 

 which proceed radical tubes. The dorsal structure is just the same as that of Lepralia 

 dorsipora, as radical tubes in that case also proceed from the " large oval or reniform 

 openings." 



This may be related to Lepralia vicina, Reuss, Foss, Bry. (Est-Ung. Mioc, 

 Taf. vii. fig. 10. 



o" 



Aspidostoma gigantea. Busk (PI. I. figs. 16-18 ; PI. III. figs. 20, 21). 



Aspidostohia gifjanieum. Busk, Zool. Chall. Exp., part xxx. p. 161, pi. xxxiiL fig. 3, and .synonyms ; 



Jullien, Bryozoaires, Mission du Cap Horn, p. 77, pi. vi. 

 Micropora caiata, Waters, Quart. Journ. Geol. Soc, vol. xxxix. p. 435. 



lu the Challenger specimens the " penthouse-like projection " is quite distinct on the 

 two sides, and in many cases each divides and forms a solid cervicorne process. 



