304 Mr. H. J. Carter on 



the margin, after which it becomes homogeneous and smooth, 

 as it lines a large cloacal cavity into which the great canals 

 of the excretory systems empty themselves ; oftentimes the 

 vent is double, and sometimes accompanied by one or more 

 subsidiary ones. Internally the fibrous structure radiates 

 upwards and outwards from the stem, consisting of main and 

 interuniting fibre, of which the former is cored with sand &c. 

 and the latter simple, forming a reticulated mass whose inter- 

 stices are tympanized by the parenchymatous sarcode, 

 traversed by the branches of the excretory canal-systems, 

 which finally open into the cloaca. Size variable, under 5 

 in. high and 3 in. in diameter horizontally in its widest part. 



Hah. Marine. 



Loc. Port Phillip Heads, South Australia. Depth 19fath. 



Obs. When acquainted with the typical form of this species 

 with its sarcode off] that is with the dried washed-out skeleton, 

 it is not difficult to recognize it with the sarcode on ; but the 

 two are necessary for identification. Hence the necessity of 

 knowing both, which, unfortunately, is the case with most of 

 the Psammonemata, on account of the sameness of the fibre, 

 the variety of structure even in the same species, and the 

 absence of any particular form of "proper spicule" to 

 characterize the individual. I say " unfortunately," because 

 the species are so numerous, so very varied in their forms, and 

 so seldom obtained in both the conditions above mentioned, 

 that it will, as above stated, be a long time before they can be 

 fully and faithfully recorded for practical utility. 



In many of the dried skeletal specimens in the British 

 Museum the walls, made up of the columnar fibre described 

 by Schmidt, present a distinctly hexagonal or honeycomb 

 structure, extending inwards towards the centre, and in some 

 instances three or more pyriform individuals have grown 

 together ; the vents, too (as before stated), are by no means 

 always single, and are sometimes supplemented by smaller 

 ones ; but the varieties in form and structure of the entire 

 sponge, and even the state of its dermal surface, are so great 

 that, if each has to be particularly described, I doubt whether 

 Schmidt's description of the fibre alone will suffice for iden- 

 tification. 



With reference to nomenclature, it might be observed that 

 Dr. Bowerbank called his specimen " Halispongia choanoides " 

 in 1872 (I. c.) after Schmidt had established the generic 

 name " Stehspongos " in 1870 {I. c.) ; to which, however, it 

 should be added that the former did this only provisionally, 

 although, as the context shows, evidently without any allusion 

 to, if acquainted with, what Schmidt had done previously, 



