38 Mr. H. J. Carter on Specimens 



microspined round head, 27 by l^-1800th (fig. 1, b) ; 3, 

 hair-like, smooth, acuate, about 17-1800ths long (fig. l,d) ; 



4, thick, fusiform, slightly curved, shaft with inflated round 

 and microspined extremities, 17-1800ths long (fig. 1, c) ; 



5, flesh-spicule, smooth, tricurvate, 12-6000ths long (fig. 1, 

 e, g)) 6, flesh-spicule, equianchorate, naviculiform, 4-6000ths 

 long (fig. 1, f\ g). Nos. 1-4 form, in plurality, the tuft, 

 of which 3 is the most numerous, and all have their long 

 axis respectively outwards ; 5 and 6 are plentifully dis- 

 tributed about the base of the tuft. Size of specimen (which 

 is imperfect) about If inch long, stem 1-1 Oth inch in dia- 

 meter. 



Hab. Marine. Growing on hard objects. 



Loc. Gulf of Manaar. 



Obs. This well accords with the genus Dictyocylindrus as 

 established by Dr. Bowerbank. The thick short spicule with 

 inflated and microspined extremities (no. 4) may be con- 

 sidered the echinating form. 



Diclyocylindrus sessilis, n. sp. (PI. IV. fig. 2, a-d.) 



Massive, convex, sessile, spreading, becoming subhemi- 

 spherical (PI. IV. fig. 2). Consistence hard, rigid. Colour 

 light brown. Surface uniformly uneven. Structurally com- 

 posed of tongue-shaped columns radiating and branching 

 from the base to the circumference, where they are more or 

 less divided, and thus altogether, when dry, present the ap- 

 pearance of a cauliflower, consisting of tufts of spicules densely 

 packed together, and rendered almost inseparable without 

 fracture by their tough sarcodic union. Spicules of three 

 forms, viz. : — 1, large, stout, smooth, acuate, curved chiefly 

 towards the blunt end, which is slightly larger than the shaft, 

 45 by 2-1800ths (fig. 2, a) ; 2, thin, hair-like, smooth, acuate, 

 about 20-1800ths long (fig. 2, b) ; 3, flesh- or echinating 

 spicule, shaped like no. 1, but spined throughout, sparsely 

 towards the large end, 35 by 2-6000ths (fig. 2, c, d). The 

 large acuates are surrounded by bundles of the hair-like ones, 

 having the echinating spicule at their base, to form, all together, 

 the "tuft." Size of specimen about 6-12ths inch high in the 

 centre by 1\ inch in horizontal diameter. 



Hab. Marine. Growing on hard objects. 



Loc. Gulf of Manaar. 



Obs. In this, as in many other species of the Echinonemata, 

 the tufts, when dissected out, will be found to be almost iden- 

 tical in form with those of Microciona atrosanguinea 7 Hk., show- 

 ing not only an alliance between the two genera,but X\\^t Dictyo- 

 cylindrus is only a more complicated structure of 'Microciona. 



