

NOTES ON THE VARIATIONS OF RHEGMATODES. 369 



tacular spurs or clubs between the bases of the fully developed 

 ones. 



In view of the constantly increasing number of these organs, 

 which are the more prominent organs usually involved in varia- 

 tion, it might seem a very uncertain problem to undertake any- 

 thing like a critical determination of the quantitive variations. So 

 far as the merely numerical aspects of variation are concerned 

 this is undoubtedly true, as will be seen. I may, therefore, say 

 in the outset that, both in view of the doubt just expressed, as 

 well as in the comparatively small number of specimens avail- 

 able, no attempt will be made to present anything like a statis- 

 tical account. It will be the purpose, rather, to submit a brief 

 account of variations of a quantitative, or substantive character. 



So far as I am aware, the only account of variations in the 

 Family yEquoridae is that submitted by Claus, l concerning 

 sEqnorca forskalii in a sharp critique of Haeckel's multiplication 

 of species, and enlargement of the scope of the family. Claus 

 calls attention to the striking differences exhibited by young spec- 

 imens as compared with adults, and also to the almost equally 

 marked differences as to coloration found in specimens of various 

 ages and sexes, as well as to the highly variable character of the 

 number of canals, shape of mouth and oral arms under different 

 conditions of contraction, etc. 



In connection with his description of Rhegmatodes floridana, 

 Dr. A. Agassiz has merely referred to the fact that in the /Equo- 

 ridae, " the chymiferous tubes especially are very irregularly 

 formed. They are frequently added all on one side of the 

 spherosome, and almost fully formed before they begin to develop 

 in the other half." 2 



The matters involved in these observations, while both of im- 

 portance, hardly touch the more fundamental problems of varia- 

 tion as now understood. The critique of Claus is eminently 

 fitting as a protest against the unwarranted multiplicity of species 

 based upon such flimsy characters 'as those cited. The matters 

 referred to by Agassiz deal more directly with phases of develop- 

 ment than with those of variation, though closely related thereto, 



1 Arbeit. Zoolog. Inst, Wien, iSSi, p. 283. 



2 " North. Am. Acalephre," 1865, p. 97. 



