392 PROF. E. A, MiNCHiN 0J«: THE BRITISH [Dec. 13, 



make sucli a blunder*, since not only have I found monaxons well 

 developed and abundant in his type specimen, No. 1 of my list 

 below, but it is evident he himself saw them, since he founded 

 one of his usual " connexive " varieties, Ascandra hotryoides. 



Haeckel further distinguished two varieties, ellisii and solanderii, 

 the former with the " apical ray of the quadiiradiates slightly 

 curved, the lateral rays 7 or 8 times as long as thick, the unpaired 

 angle 130°-150°" ; the latter with the "apical ray of the quadri- 

 i-adiates straight, the lateral rays 5 or 6 times as long as thick, 

 the unpaired angle 150°-180°." Since all these variations can be 

 found in any specimen, Ha,eckers two varieties may be struck out 

 of the systematic list. As I have also pointed out above, there is 

 nothing in Haeckel's description of Ascandra nitida to separate 

 it fi'om hotryoides ; A. nitida is, in fact, distinguished from 

 A. botrys by the same characters practically as Ascaltis hotryoides 

 var. solanderii from var. ellisii. 



Of writers subsequent to Haeckel, Fristedt alone [9] seems to 

 have penetrated Haeckel's mistake, since he calls the species 

 Ascandra hotryoides^ as Haeckel ought to have done. Fristedt 

 has, moreover, gone a step further, and has put variahilis as a 

 synonym of hotryoides, in which he has been followed by Vasseur 

 [23]. I have been sorely tempted to follow Fristedt's lead also, 

 and to place both forms as well-marked varieties of one species, 

 for which, of course, the name hotryoides would have to be main- 

 tained ; the form ordinarily known as hotryoides could then be 

 called hotryoides var. typica, and the other hotryoides var. varia- 

 bilis. As has been shown above, the difference between the two 

 forms is purely one of degree in every respect. As regards spicu- 

 lation, they are in complete agreement, every form of spicule 

 occui'ring in the one being represented also in the other, and the 

 special features of hotryoides are merely an exaggeration of those 

 of variabilis. As regards external form, variabilis occurs in a 

 variety of situations and consequently varies in form ; the fact 

 that in hotryoides the habits both of situation and growth are 

 constant, is in itself highly suggestive of its being a form-variety 

 adapted to a particular environment. Examination of the sponge 

 bi'ings to light a further very important fact, beaiing directly 

 upon the question under discussion, namely, that the thickened 

 triradiate systems so highly characteristic of hotryoides are nearly 

 absent, or comparatively scarce, upon the basal network of tubes 

 by which the sponge is attached to its support, but are greatly 

 developed as a protecting and supporting layer upon the erect 



* The only source I can snga'est for Haectel's error with regard to the monaxons 

 of hotryoides is the fact that Bowerbank also failed to see monaxons in this species, 

 and considered their absence as one of the characters distinguishing it from his 

 Leuoosolenia contorta. If my notion be coiTcct, this is a curious case of successive 

 incarnations of an error, manifesting itself first in Bowerbank 1866, then in Haeckel 

 1872, and for the last time, let us hope, in Breitfuss 1898. A still more remarkable 

 point in this history is the fact pointed out above, that the specimen from which 

 Bowerbank described the spiculation of hotryoides was really a specimen of 

 ■vdriahilis (Haeckel), while the specimen of " contorta " from which he figured 

 luuuaxons was in reality a specimen of complicata \ 



