454 Mr. H. J. Carter on 



verse diameter. Body-substance yellowish grey in colour. 

 Spicules of two kinds, viz. skeletal and flesh-spicules : — 1, 

 skeletal, inflated at each end, or with one end more or less 

 sharp-pointed, varying greatly in size, the thickest in the 

 mounted preparation l3eing about 90 by 2^-6000ths in., and 

 the thinner ones about 180 by l|-6000th in., but hardly any 

 two alike in this respect ; 2, flesh-spicule, a simple navi- 

 •cular-shaped anchorate of the common form, about 8-6000ths 

 in. long. No. 1 is the skeletal spicule generally, and no. 2 

 the flesh-spicule, which is most abundant in the clathrous 

 structure of the appendages. Size of specimen now dry and 

 corrugated about ^ in. high by 2 in. in horizontal diameter; 

 bearing upwards of twelve appendages. 



Loc. Port Western. 



Ohs. The same observations ap])ly to this species as to the 

 foregoing one, H. verrucosum. Without microscopical exami- 

 nation of their elementary parts it would be very easy to 

 mistake both species for specimens of Polymastia. 



Pseudohalichondria clavilohata, n. sp. (PI. X. figs. 6-9.) 



Specimen large, massive, composed of several claviform 

 lobes of different sizes, large and small, united together into 

 a common mass, which becomes contracted towards the base 

 into a substipitate form, expanding again below, to produce 

 the root-like attachment (PI. X. fig. 6). Consistence sub- 

 compact, yielding. Colour yellowish white. Surface even, 

 presenting a stout, soft, fibro-reticulation (fig. 9, a a), indis- 

 tinctly covered with small epithelial cells and pore-areas 

 (fig. d, b b), in the midst of which are a great number 

 of circular, monticular elevations, terminated respectively by 

 a single sand-cored filament (fig. 6, bbbb, and fig. 9, c?). 

 Pores in the interstices of the fibro-reticulation (fig. 9, bb). 

 Vents small, in the prominent parts of the lobes (fig. 6,cccc). 

 Structure internally subcompact, covered with a cortical 

 layer l-24th in. thick, composed of soft, compact, fibrillous 

 structure, through which the pores, which areabout4-1800ths 

 in. in diameter, have to pass before they reach the subdermal 

 cavities ; skeletal support consisting of thick sand-fibre, 

 which, extending in more or less longitudinal lines from the 

 base upwards, branches out towards the circumference of 

 lobes, where it ends in the monticular elevations men- 

 tioned (fig. 9, d), which, from the transparency of the 

 quartz-sand coring the filaments by which these are sur- 

 mounted, presents the appearance of a punctum like a 

 small vent ; mixed with strongly developed spiculiferous 



