Polyzoa, Coelenterata, and Sponges. 455 



yellow colour. The tentacles and surface of column were ex- 

 amined for thread-cellsj none of which were discovered. In its 

 coloration and the characters of the conchula this species ap- 

 pears to be related specially to P. hastata, Gosse. 



Hydeozoa. 



Sertularella tricuspidataj Alder. 



Serhdaria tricusjndata, Alder, Trans. Tyiieside Nat, F. Club, iii. 



p. Ill, pi. iv. ligs. 1, 2. 

 Sertularella tricuspidata, Hincks, Brit. Hydr. Zoopli. p. 239, pi. xlvii. 



Several pieces, representing three or four colonies at least ; 

 robust, with the exception of one rather thin-walled colony ; 

 one colony attained a height of 2^ inches (61 millim.). A 

 few gonotheciB occurred, but all wanting their uppermost end. 

 The time of year (late summer) at which they were collected 

 evidently accounts for this agreement in the incipient disso- 

 lution of these bodies, and points to the time at which repro- 

 ductive activity ceases in this species in this latitude. 



Spongiida. 

 Calcaeea. 



Clathrina coriacea^ Montagu. 



Spongia coriacea, Montagu, Wern. Mem. ii. p. 116. 



Grantia coriacea, Johnston, Brit. Spong. p. 183, pi. xxi. fig. 9. 



Ascetta coriacea, Hackel, Kalkschwamme, ii. p. 24, pis. iii. & v. fig. 2. 



A fragment, apparently torn from a Soleniscus-gxcmih. ; the 

 diameter of the tube must have been about 1*5 millim. Colour 

 opaque white. The spicules have the somewhat iuequiradiate 

 character which I have recently found in those of a specimen 

 from South America ; their rays measure respectively '10135 

 by -0079, -076 by "0079, -076 by '0079 millim. average maxi- 

 mum dimensions, and should therefore be described as 

 "sagittal" according to Hiickel's nomenclature. The diffe- 

 rence in length between the rays is not so great in some of the 

 spicules. 



Dr. Gray's genus Clatkrina (P.Z. S. 1867, p. 557) has the 

 priority of Hackel's Ascetta^ published in 1872. 



This widely spread species has already been recorded from 

 the Arctic regions, viz. by Mr. Carter (' Annals,' ser. 4 

 vol. XX. p. 38) from Smith's Sound, and from the European 

 side of the Pole (Barents Sea) by Von Marenzeller (Denk. 

 Ak. Wien, xxxv. p. 371). 



