192 Mr. H. J. Carter on Grayella cyathophora, 



thus easily be mistaken for a coral. It did not, however, 

 escape the keen discrimination of Mr. M'Andrew ; and hence 

 we are provided with a species which at once brings the sponges 

 a step nearer to the corals in forrn^ and one which may now 

 and hereafter throw much light on the true nature of many 

 fossilized species that otherwise might be doubted. 



The cup-like body, averaging in its broadest diameter 1-1 2th 

 of an inch, far surpasses in size anything of the kind hitherto 

 met with in the sponges. Witness a similar apparatus which 

 I have lately described and figured in PachymatismaJohnstonia 

 (Annals, this volume, pi. 2. fig. 12 &c.), where it is depressed 

 and not more than a quarter the diameter of the cup-like body 

 in Grayella cyathophora. 



This, too, I think, is the first instance on record where the 

 pore (for such is the nature of the cup-like body) has been 

 shown to be in direct communication with the excretory canals. 



Although the surface of the dermal layer between the cup- 

 like bodies is minutely papillated, and each papilla might, in 

 the recent state, have presented an aperture, which the sponge 

 itself, or the astringency of the spirit in which it was preserved, 

 may have closed, I only saw one here and there ; and these 

 were as often in the depressions between as upon the papillae 

 themselves. Hence I am inclined to infer that such apertures 

 are adventitious. In some instances they appear to be the 

 buds of new cups ; but for the most part the dermal layer 

 is perfectly smooth, and hirsute only over the cribriform disks. 



The cups, again, have the power of closing themselves ; but 

 whether this is produced by the general contraction of the 

 reticulated sarcode of the cribriform disk, or by that of the 

 walls of the cup alone, or by both synchronously, I am igno- 

 xant. When, however, it does take place, the cups, in suc- 

 cessive degrees of contraction, show that the apertures of the 

 cribriform disk are more or less closed by the approximation 

 of the reticulated structure; and the margin generally yielding 

 as well, causes the cup to assume a conical form, puckered at 

 the apex and ribbed vertically down its sides, in the manner 

 of a coral-polype (fig. 9 a, h^ c). 



After the water has passed through the concave cribriform 

 disk (convex or flat when living?), it reaches the internal 

 cavity or chamber of the cup, and thence flows on to the con- 

 stricted end of the funnel-shaped prolongation, which, being 

 provided with the circular ribs or ruga? of sarcode mentioned, 

 may also have the power of total closure, especially at the 

 point where it opens into the commencement of the excretory 

 canal to which it is attached (fig. 5 c,f). 



The excretory canal, too, is observed to be much wider than 



