dredged up from the Gulf of Manaar. 135 



Ohs. The spiculation of this is very much like that of the 

 last species, viz. G. ramodigitata; but the addition of 

 the globostellate (no. 5), which is also present in an em- 

 bryonic specimen of the same species, with an entire absence 

 of pin-like spicules in both instances, whose presence would 

 immediately claim for it a Hymedesmid origin, seems to 

 indicate that it is produced by the Geodia itself, and thus 

 distinguishes the latter from all other species that I have yet 

 encountered. This form of globostellate, however, is so 

 unusual in Geodia, and so common about the Manaar speci- 

 mens with one or more Hymedesmids, of which it forms the 

 basal layer (ex. gr. H. stellivarians &c), that I can hardly 

 suppose it would be present in Geodia under any other circum- 

 stances. Still, from what has been stated, and my inability 

 to find any traces of a pin-like spicule in the midst of the 

 petrous crust where these globostellates are present, I am 

 unable to regard it otherwise than as a product of the Geodia, 

 where it may be an enlarged form of the dermal stellate. 

 Another character of this species is the great number of 

 " fork " spicules that project through its surface, among 

 which I have not been able to discover a single " anchor- 

 head." 



Stelletta euastrum, Sdt. (PI. VII. fig. 41, a-l.) 



Laminiform, thin; growing parasitically over groups of 

 Siliquaria anguina, and therefore presenting no definite form. 

 Colour greyish white (PI. VII. fig. 41). Surface even. 

 Pores minute in the dermal sarcode. Vents in groups or 

 scattered singly here and there. Spicules of five forms, 

 viz. :— 1, the zone-spicule, with simple trifid head or with the 

 arms more or less divided (that is, the prongs of the furcation 

 more or less lengthened), the whole expanded laterally at 

 right angles to the shaft, which is from 20 to 40 by 4-1800ths, 

 head 27-1800ths in diameter, both shaft and head being very 

 variable in form and size (fig. 41, b); 2, body-spicule, acerate, 

 smooth, curved, fusiform, 60 by 2-1800ths (fig. 41, c) ; 

 3, siliceous globule, discoid, irregularly elliptical, very thin, 

 the hilous depression hardly discernible, and the stellate ends 

 of the radiated structure scattered thickly but separately over 

 the surface, about 17 by 9-1800ths and about 3-1800ths thick 

 (fig. 41, d, g, k, I) • 4, acerate (flesh-spicule), curved, micro- 

 spined, more or less inflated in the centre (fig. 41, e, g } h) ; 

 5, stellate, 2-1800ths in diameter (fig. 41, e, g, i). Siliceous 

 disks gathered together in a thin layer on the surface, but the 

 rest of the spicules mixed together apparently indiscrimi- 

 nately and confusedly throughout the body ; the zone-spicule 



10* 



