458 Mr. H. J. Cm-tei- on 



Ecccelonida. 



Cliona celatttj Grant. 



Infesting the shell throughout of a large smooth bivalve, 

 about 2| in. long and 2^ in. high. 



Vioa Jolmstonti, Schmidt. 

 J'ioa Jolinstomi, Atlantisch. Spongienf. 1870, p. 5, Taf. vi. tig. 18. 



This carmine-coloured boring sponge, which, for the most 

 part, is concealed under the calcareous crust of a 3Ielobesia, 

 presents itself externally under the form of little heads filling 

 circular holes of the same size among the conceptacles of the 

 Melohesia, where, under a 2-incli lens, it maj be easily recog- 

 nized by its bright carmine colour. The holes, which are 

 about l-48th in. in diameter, are occupied by the pore-areas 

 and vents respectively, as in all other sponges of the kind, 

 the latter being, as usual, provided with a sphinctral sarcodic 

 diaphragm. {Spicules of two kinds, viz. skeletal and flesh- 

 spicules : — 1, skeletal spicule, pin-like ; 2, Hesh-spicule, a 

 spinispirula of four bends, about 10-6000ths in. long. 



Loc. Port Western. 



Obs. This chiefly differs from Vioa Johnstomi in the spicu- 

 lation being smaller than that of the Adriatic species, but not 

 sufficiently to constitute in any respect even a variety. 



Stelletta ochracea, n. sp. 



Specimen irregularly cylindrical, bolster-shaped. Colour 

 bright ochre-yellow throughout. Surface even. Pores in 

 juxtaposition over the surface generally. Vents few and 

 scattered here and there. Structure compact, without marked 

 cortex, but possessing a superficial layer of large epithelial 

 cells mixed v.'ith small acerates and minute bacillar spicules. 

 Epithelial cells 8-6000ths in. in their longest diameter, and 

 the "granules" (cellulai) which contain the yellow colouring- 

 matter about l-|-6000tli in,, the latter plentifully extrava- 

 sated into the tissue generally, which gives the species its 

 yellow colour. Spicules acerate, trifurcate, and bacilliform : — 

 1, acerates of two sizes, both alike in form, one, the larger, 

 about 240 by 6-6000ths in., constitutes the usual body- 

 spicule, and the otlier, or smaller, the flesh-spicule of the 

 surface, varying under 35 by l-60U0tli in. : 2, trifurcate, con- 

 sisting of three straight arms, radiating at equal angles from 

 each other, each of which is furcated, that is divided into two 



