Manchester Memoirs, Vol. /,•//. ( , 9 , ;) , , $ 



has made most exhaust ve ,-el T tW ° f °', mS - •»' J" Listei * 



his observations he sums un as follows "\v results ot 



then thai- «-h„ ™;„ i l /oilows . — VVe may conclude 

 tnen, that the microsphere and megalospheric forms of the 

 Foramirufera represent alternating or recurring ge ier" tio s 



Lxuii r y e, h- ^ hi,e the ^4 S P heHc infralion arise 

 asexually either from a nncrospheric or a meealosoheric 



se'xuaHv'S 15 P1 h° b H le that the '"--P'-ric genTrattEs 

 sexual y, ,.e by the conjugation of two similar zoospores." 

 Hei e it may be said that the megalospheric form in Nummulites 

 is always very much more numerous than form R. 



A revision of the nomenclature of the Nummulites is now 

 recognised as necessary, and M. Van den Broeckt sbu put for 

 ward two schemes both of which have something in their favour 

 Ihe first consists in retaining the specific name of Form A 

 and considering that the normal tvpe on account'of its numerical 

 superiority over Form B. Though both convenient and secur 

 ing a biological unity of the group, this scheme violates the 

 rules of zoological nomenclature as regards the priority 

 of specific names ; in some cases the megalospheric form having 

 been first discovered, and in others the microsphere having 

 been the first to receive a specific name. The second scheme 

 consists in respecting the law of priority of name, but in this 

 case there is the difficulty of the specific name retained being 

 sometimes that of the microsphere, and at others that of the 

 megalospheric form. Personally I am in favour of the first of 

 Van den Broeck's proposals, as there have already been excep- 

 tions made to the priority rule in favour of several other 

 groups of Animals, and I do not see why the same advantages, 

 should not be accorded the Foraminifera, particularly as such 

 a course would settle the question under consideration, in fact, 

 without such a solution I can see no way at all out of the 

 difficulty. In my record of the Biarritz Nummulites I propose 

 to treat the "couples" under one heading, giving both specific 

 names, but it will be quite clear that the two forms are refer- 

 able to a single species, whatever may be the specific name 

 eventually adopted. 



Below I give examples of the two schemes proposed by 

 Van den Broeck, and as the same forms are given in both exam- 

 ples, it will enable an opinion to be formed of their respective 

 merits. 



* A treatise on Zoology, edited by E. Ray-Lankester, p. 77. 

 t " Comment faut il nommer les Nummulites en tenant compte de leur 

 Dimorphism." Bulletin Soc. Beige de Geologie, Tome X. 1896, pp. 50-62. 



