370 REVISION OF THE MONAXONlD SPONGES, II., 



exhibit a conspicuous resemblance to tiie type-specimen of Stylo- 

 tella digitata ( = S. agminata). While external examination of 

 the specimens afforded no reason to doubt that at least the more 

 massive-looking would be found in complete conformity with the 

 description of T. laxa, microscopical examination yielded, in every 

 case, the same result, and showed them to be no more than a series 

 of forms of Stylotella agminata. Yet, at the same time, there was 

 presented the very striking coincidence that, in the arrangement of 

 their skeleton and approximate size of their spicules, the specimens 

 actually do agree with the description of T. laxa, almost perfectly. 

 In the face of such evidence, a contention that the specimens are 

 other than examples of this species cannot well be sustained; and 

 one has to conclude that Tedania laxa is no more than a synonym 

 of Stylotella agminata. The probability of the correctness of this 

 conclusion is supported by other considerations, as follows: — 

 According to its description, T. laxa differs from S. agminata only 

 in the following particulars ; the sponge grows to a comparatively 

 large size (nearly twice that of the largest specimen of S. agminata 

 in the collection) ; oscula are not apparent; the colour of the living 

 sponge is bright brick-red; and the spicules, in addition to styli, 

 include tylota, oxea, and rare trichites. But the difference in mere 

 size of the sponges is of very doubtful importance, as also is their 

 difference in colour ; the oscula of S. agminata are often very diffi- 

 cult to make out (owing apparently to their becoming closed over, 

 as a result of contraction, by the dermal membrane) ; and there is 

 present, in this species, a small proportion of slender megascleres 

 which, without critical inspection, could very easily be mistaken for 

 trichites. Also, allowance must be made for the fact that, in regard 

 to matters of spiculation, the Catalogue is often seriously at fault; 

 and of especial significance in this connection is the erroneous 

 spiculation ascribed to Tedania rubicunda and T. rubra. And, 

 finally, it is to be noted that the pattern of the skeleton of S. agmi- 

 nata bears no inconsiderable resemblance to that (in certain parts) 

 of T. rubicunda, and, indeed, might be described in precisely the 

 same terms as Lendenfeld, in his description of the latter species, 

 employs. 



