Mr. H. J. Carter on the Sarcohexactinellid Sponges. 281 



in Hyalonema with the terminal hooks present, that I have 

 only observed it in four instances, and all in one small speci- 

 men, of which the body is half an inch long and the cord of the 

 same length. They occur close to the body, while those which 

 were at the ends of the longer spicules forming the cord have 

 all, as usual, been broken oiF. In this case, too, they are on 

 the spined and not on the smooth spicules. As regards the 

 jMsition of the hooks, they are double, and both on one side 

 like a claw in two of the instances, and in the other two triple, 

 but two of these appear to be op})osite, anchor-like. Fortu- 

 nately they are not all the same in all four instances, or the 

 inference might have been that the terminal hooks of these 

 spicules in Ilyalonema were all on one side, claw-like, or all 

 opposite, anchor-like, as the case might have been ; still the 

 third spine in the latter also gives a lateral predominance. 

 The specimen, which is mounted, was dredged up on board 

 H.M.S. ' Porcupine,' and sent to me by Prof. W. Thomson. 

 It bears no polype on the cord. 



The little crucial-headed spicule of the surface in Laharia^ 

 with its plumose shaft ready to be depressed as the arese about 

 which it is situated may require to be more or less closed, is 

 common to the sponge part of Hyaloneina {Gartena^ Gray), 

 lloltenia^ and PJu'ronema Grayij and probably also to Phero- 

 netna Annce, Leidy, with the exception of the arms being thickly 

 spined instead of smootli, as before mentioned. 



Then No. 4, the birotulate spicule ("multidentate," Bbk., 

 f. 60), of all sizes below its largest form (for it should be 

 borne in mind that they grow from small to large), is also 

 specifically characteristic of Ili/alonema, Holtetiia, and Phe- 

 ronema Grayi. No other sarcospiculous hexactinellid that 

 I know of possesses this spicule ; and therefore I am at a 

 loss to conceive how Schmidt should have named the sponge 

 described and figured by him in his ' Atlantisch. Spongien- 

 fauna' (p. 14, Taf. 1. figs. 1-6) " Holteniar 



In Rossella velata^ W. Thomson, and BosseUajyhiUjyj^inensisy 

 Gray (which are sarcospiculous, hexactinellids), we may observe 

 "the '«»'««te, equiarmed, hexradiate spicule" to pass from (1st) 

 the equiarmed hexactinellid with bifurcated and pointed cxti'e- 

 mities, to (2nd) the same with capitate extremities (" s])inulo- 

 stellate," Bbk., f. 190), and, lastly (3rd), into an undescribed form, 

 Avhere the ends of the arms are terminated by a small, conical, tu- 

 bercled inflation, presenting a short straight spine on the apex, 

 which spine is surrounded by almost innumerable linear 

 filaments rising each from one of the tubercles, attaining 

 various heights, and liending outward like the expanded 

 petals of a tubular flower, forming one of the most exquisite 



