42 Mr. H. J. Carter on Specimens 



around no. 1. Size variable; that of specimen about \ inch 

 in horizontal diameter. 



Hab. Marine. On hard objects. 



Log. Gulf of Manaar. 



Obs. The large inflation of the. fixed end, which is turned 

 to one side, occurs in all the spicules except no. 4. There 

 are no anchorates and no tricurvates ; so that the spiculation 

 is something like that of HymerhapJiia clavata, Bk. ; but, as 

 above stated, all the spicules are erect like those of a Micro- 

 ciona, whereas in Dr. Bowerbank's illustration of that species 

 (B. S. vol. iii. pi. xxvi. fig. 4) part, at least, are reclined con- 

 fusedly ; but then, as I have also said before, this may 

 have been occasioned by circumstances, viz. protection or 

 exposure respectively during growth. 



Microciona quadriradiata, n. sp. 

 (PI. IV. fig. 4, a-d.) 



Laminiform, extremely thin, hirsute, spreading. Colour, 

 when dry, dark brown. Spicules of three forms, viz. : — 1, 

 large, setaceous, smooth, acuate, curved chiefly towards the 

 blunt end, which is globular and rather less in diameter than 

 the shaft, from which it is separated by a slight constriction, 

 75 by 3-1800ths (PL IV. fig. 4, a) ; 2, thin, smooth, acuate, 

 frequently more or less crooked, 25-1800ths long (fig. 4, b); 

 3, quadriradiate, consisting of three arms radiating at equal 

 angles from a common central point, which, raised and tripod- 

 like, supports the fourth arm in an erect position ; all densely 

 and uniformly microspined, 5^ by 6-1800ths (fig. 4, c, d). 

 No. 1, together with tufts of no. 2, projects vertically out of 

 the lamina, which is densely charged with no. 3, whose erect 

 arm thus becomes the echinating spicule. Size variable ; that 

 of specimen about \ inch in diameter. 



Hab. Marine. On hard objects. 



Loc. Gulf of Manaar. 



Obs. The quadriradiate spicule of this species is almost 

 identical in form with that of Dictyocylindrus Vickersii 

 (' Annals,' 1879, vol. iii. p. 292, pi. xxvii. figs. 5-8), where 

 the vertical arm in like manner becomes the echinating element 

 or spicule ; and the crooked form of the thin acerate is also 

 similar ; but the skeleton- or setaceous spicule is different. 

 In the species, however, to which Mr. Thomas Higgin has 

 called attention, and which also grew on a Mehbesia (" Nulli- 

 pore"), both the quadriradiate and setaceous spicule are 

 essentially identical ; therefore this is a specimen of Microciona 

 quadriradiata from the West Indies (' Annals,' 1877, vol. xix. 

 p. 296, pi. xiv. fig. 9). 



