50 Mr. H.J. CixvteY on 



and the stouter one with lanciform end to the surface, the 

 latter also mingling (as before stated to be the wont of the 

 surface acerates) with the proximal ends of the peristome 

 spicules ; no. 2, the triradiates in their largest size occupying 

 the position mentioned 5 and no. 3, the quadriradiates, mixed 

 with the small triradiates, in the cortex and the cloaca respec- 

 tively ; in the latter, the fourth arm is short, small, and 

 so sparse as to be hardly noticeable. Size of specimen, which 

 of course, from its composition, is very irregular, about 1^ in. 

 each way. 



Ohs. On tlie surface of tlie cloaca may be seen small holes 

 about 1-lOOOth in. in diameter, which appear to be pores like 

 those of tlie surface, as I have before stated ; and here I would 

 observe again that if the differences in form, position, and 

 size of the spicules respectively in a Calcareous Sponge are 

 to be severally noted, it must be done in a special description 

 of the species itself, which would thus become far too elabo- 

 rate for practical purposes, so that, in a Handbook of Sponges 

 generally, some medium course must be adopted to attain tliis 

 object. 



23. Heteropia macera. 



Agglomerate. Consisting of several individuals united 

 together, whose form separately would be cylindrical, sacci- 

 form, and peristomed. Colour whitish yellow outside, sponge- 

 brown within. Surface even, uniformly consisting of 

 moderately large triradiates fixed in position by cribriform 

 sarcode. Pores, the holes of the cribriform structure, which 

 are very distinct but not particularly large. Vents of the 

 individuals respectively terminal, circular, and eacli provided 

 with a peristome, leading into a general cloacal cavity, which 

 is narrow and cylindrical at first, but afterwards becomes 

 wider than the wall of this cavity as it spreads itself out into 

 the cloacal dil-atations of the rest of the individuals in the 

 mass ; lioles of the cloaca large generally, but still variable in 

 size and distance apart, corresponding with the variable width 

 of the skeletal structure of the surface of the cloaca. Structure 

 of the wall like that of the last species described, viz. H. 

 paiuloscidifera, that is, consisting of horizontal intervals de- 

 fined by the long shafts of sagittal triradiates which, coming 

 from opposite sides of the wall, overlap each other, while the 

 intervals, which are chiefly composed of sarcode, intercom- 

 municate with each other by large holes in addition to the 

 usual pores. Spicules of two kinds, viz. acerate and trira- 

 diate ; no quadriradiates : — 1, acerates, of three forms, viz. 

 that usually composing the peristome, among which proxi- 



