72 



ME. H. J. CAETER ON A COLLECTION OF 



projects from the surface here and there in pointed terminations 

 like small spines. No. 57 (PL VII. figs. 1-3), which is the 

 largest of these specimens, is about 9 by 5 inches in horizontal 

 diameter and 3 inches high, composed of hollow branches sub- 

 dividing and anastomosing so as to form a continuous structure, in 

 which the free ends of the branches on the surface are inflated, 

 and each presents a circular hole in the centre, which is the oscular 

 termination of the tubular interior. The rest all grow over the 

 surface of the stems of thread-like Gorgonice, with the exception 

 of ~No. 74, which is a small specimen on a piece of rock. 



Halichondria. bieottjlata, Higgin, Ann. Sf Mag. Nat. Hist. 

 4th ser. vol. xix. p. 296 (1877). 



This reddish-purple or claret-coloured sponge, originally de- 

 scribed from a West-Indian specimen by Mr. Thos. H. Higgin, 

 F.L.S., is represented by a small portion (No. 69) growing over 

 a piece of old branched coral. It is also abundant on the S.W. 

 coast of Australia, and probably occurs in other parts of the 

 world. 



Espeeia pltjmosa, Carter, Ann. Sf Hag. Nat. Hist. 5th ser. 

 vol. ix. pp. 298, 299 (1882). 



Is plentifully represented, and appears to be identical with the 

 form from Mauritius to which I have given the above name. 

 Most of the specimens have grown over the stems of thread-like 

 Gorgonice, where they present a spinous appearance as if they had 

 grown over a layer of Dysidea ramoglomerata ; while the anfrac- 

 tuous, irregular growth of the two separate ones, viz. Nos. 37 

 and 68, although more massive, present no specific character 

 whatever in this respect. The fragility of the species has caused 

 No. 37 during transit to become broken, so that, although 

 apparently of great dimensions when entire, it now only presents 

 fragments, of which the largest is only 3 inches in its longest 

 diameter. In some parts of these specimens the tricurvate is 

 replaced by the sheaf-shaped spicules ( ; ' trichites," Sollas), which, 

 as I have before stated, appear to me to be only a straighter form 

 of the tricurvate flesh-spicule ; while the minute cquianchorate 

 of E.plumosa (I.e. pi. xi. fig. 19, a, h) is very abundant. 



EsPEBii dic a , q. sp. (Plate VI. figs. 3-6.) 

 Massive, sessile, Jobate, taking the form of the bottom-detritus 

 (shells and stories) over and among which it has grown, or rising 



