60 On Specimens dredged up from the Gulf of Manaar. 



Samus simplex, n. sp. (PI. V. fig. 26, a-c.) 



Occurring as just mentioned. Colour that of dried sarcode. 

 Spicules of two forms, viz. : — 1, a short shaft with trifid 

 head once divided (trifurcate) , the whole expanded at right 

 angles to the shaft, 15 by 3-1800ths (PI. V. fig. 26, a, b) ; 

 2, minute or flesh-spicule, consisting of a straight shaft 

 spined throughout irregularly, spines most prominent towards 

 the ends, 3-6000ths long (fig. 26, c). Size of specimen 

 variable, concurrent with that of the excavated cavity, which 

 may be l-6th inch in diameter. 



Hob. Marine. In excavations of the Melobesian nodules, 

 towards the surface. 



Loc. Gulf of Manaar. 



Obs. This is the simplest form of /Samws-spicule that I 

 have met with ; hence the designation of the sponge to which 

 it belongs. 



J .-y 



Samus (Pacliastrella) parasiticus. 

 {' Annals,' 1876, vol. xviii. p. 410, pi. xvi. fig. 50 &c.) 



This species, which I formerly called " Pacliastrella para- 

 sitica" (I. c), occurs abundantly in excavations of the Melo- 

 besian nodules, accompanied by both forms of its flesh- spicules, 

 viz. the spined bacillar form, fig. 50, d (I. c), and the 

 spinispirula, fig. 50, f (I. c). Originally I did not know the 

 habitat of Samus parasiticus ; but seeing that it so much resem- 

 bled Dercitus niger, Gray, in spiculation, and finding the latter 

 in company with a Cliona (to which I have before alluded) 

 in excavations of marine calcareous structure (old coral) from 

 the island of Cuba, I at once thought that Samus parasiticus 

 must be closely allied to it, and hence gave it the generic 

 name of " Pacliastrella" which now should be abandoned for 

 " Samus." At the same time I would here observe that the 

 presence of the spicules of Dercitus niger (Hymeniacidon 

 Bucklandi, latterly Battersbya Bucklandi, Bk., 1870) with 

 Cliona either shows that Dercitus niger is an intruder of this 

 kind occasionally, or that this is part of the habitat of this 

 great, massive, liver-like black sponge so common on our 

 shore-rocks. Be this as it may, there is so much relationship 

 between the Pacliastrella} (Schmidt's name for the deep-sea 

 species of Dercitus, viz. P. abyssi) and Samus, that hereafter 

 I expect it will be thought desirable to at least make them 

 one group. Hence it also becomes questionable whether my 

 Pacliastrella intexta ( l Annals,' I. c. p. 409, pi. xv. fig. 41 &c.) 

 does not belong to the same category. 



