72 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



used it in the same sense iu the i)jiper imblished by him and Ketzius in 

 1842, and was followed in this use by Creplin, also in 1842. In 1843 

 Lis article of 1841 was reprinted in French in Kayer's Archives. In 

 this the German "Psorospermien" is rendered by the French "psoro- 

 spermies," both of them the exact equivalent of the general indelinite 

 English plural psorosperms. If anything is needed to comidete 

 the evidence it is found in the fact tliat not one of tliese observers 

 proposed a single binomial name. !So it is certain that tlie term was 

 used by Miiller and his immediate successors as a general group term 

 and not as a generic designation. And it was so used in 1845 by Dujar- 

 diu, and in 1851 by Leydig, neither of whom employed a generic name. 

 Further, they did not use any specific (binomial) names, all of their 

 species, like those of previous authors, being designated as "psoro- 

 spermies du brochet," " Psorosi)ermien der Ilecht," or by a similar title. 

 The first author to apjdy the binomial nomenclature to the " psoro- 

 sperms" was Charles Eobin. In his Histoire Naiurelle des Vcf/etaux Par- 

 asites (1853) were collected descri])tions and figures of nearly all of the 

 previously described forms. Robin there defines the "psorosperms" 

 as a tribe of Diatoms, as follows : 



Tribiis Psorospermeae Cli. R. 



Phycoma ex cellulis orgunicis compositura; cellulie alb;p, fusca', liitcscentos vcl 

 achromaticie. Geueratio ignota. (Pisciuui parasitica}.) 



I form tliis group to receive a certain uumber of species of parasitic forms 

 described lirst by .J. Miiller, and since carefully studied by him, Retzius, and myself. 



From the foregoing it will be seen that to the subclassic (ordinal or 

 tribal) name was appended an exceptionally clear definition. In the 

 group thus defined llobin placed a single genus, Psorospcrmia Ilobin, 

 which must, therefore, stand as the type genus of the group. His 

 generic definition was : " Gharacteres tribusJ' Kobiu fiiiled to designate 

 any particular specdes as the generic type. He reproduced descrip- 

 tions and figures of 10 forms made known by other authors, under the 

 customary headings of " psoros])erms of the pike," etc. In addition to 

 this, however, he inserted a description and figures of a single species 

 of his own, which was the only one provided with a binomial name, or 

 in other words the only species (in the nomenclatural sense) present. 

 It is plain, therefore, that this species (P. sc/ft'«ft'-M;«6>Yt' liobin) must 

 stand as the generic type.^ 



Curiously enougli, however, of all the species collected by Kobiu 

 this is almost the only one which can not be regarded as a myxosj)©- 

 ridian. That it can not be so regarded is evident from a careful exam- 

 ination of his definition and fignres. Unfortunate as it is that the 

 name Psorospermia must lienceforth be restricted to organisms having 



• In order to place the matter beyond doubt, I now propose to limit the genus 

 Psorospennia Robin, as above indicated, viz: to forms of the type of P. 8ci(ru(v-umhr(e 

 Robin, which species I propose as the generic type. I further propose Paorospermia 

 as the type genus of Robin's tribe Psorospermece. 



