Dr. Wallich on the RMzopods. 333 



alternating order. Mouth inferior, terminal, oval. Sarcode 



COLOUELESS, HAVING CHARACTEES OF THAT OF DlFFLUGIA, 



&c." {o23. cit. p. 142). 



In describing the species he sajs : — " Quadrula symmetrica^ 

 the onlj representative of its genus, is remarkable for the 

 peculiar construction of its shell, which is compressed pyri- 



form The general arrangement [of the plates] is like 



that of tiling with variable regularity. . . . Thej are not en- 

 tirely disposed with the symmetry expressed by their name, 

 for frequently smaller plates break the regular succession 

 of larger ones, and sometimes one angle of a plate replaces 

 that of a contiguous one" {ojp, cit. p. 143). And, again,. 

 " Quadrula symmetrica was first described " in 1863-64 

 " by Dr. Wallich, under the name of Diffl,ugia symmetrica^ 

 from specimens found in England. It was more recently " 

 (that is to say in 1875, or just eleven years after I described 

 and figured it) "described, and referred to a new genus, by Prof. 

 Schultze from specimens found near Dresden, Ehrenberg 

 described the same as pertaining to three different species 

 under the names of Diffiugia assulata, D. carolinensis , and 

 D. leptolepis. These, in 1871 (Abhandl. Akad. Wiss. Berlin, 

 1871, p. 246), with a number of other forms, he referred to a 

 subdivision of Diffiugia with the names of Assulina and Holo- 

 glypha. As, however, the latter would apply to the first mem- 

 bers of the subdivision indicated, which appear to be only 

 varieties^ or at most two species of Gyphoderia^ neither of the 

 names could be considered as appropriately taking precedence 

 of Quadrula^ distinctly applied to Assulina assulata^ the 

 fourth member of Ehrenberg's list" (of 1871). 



As a matter of fact, Dijflugia symmetrica is the only aber- 

 rant member of my series of new testaceous Diffiagida3 which 

 was not included in the synoptical list given at p. 240 of the 

 ^ Annals ' for March 1864, being then, as it is still, con- 

 sidered by me to have been sufficiently identified and defined 

 in any classification having for its end a systematic arrange- 

 ment based only on natural characters. Moreover, it seems 

 extraordinary that the established rules of priority and nomen- 

 clature (to which Prof. Leidy here draws such marked atten- 

 tion) should, with his sanction, have been infringed by Prof. 

 Schultze, when the latter writer, in 1875, superseded the 

 generic name given to the form in question, at the same time 

 retaining the specific name applied to it by me as distinctly 

 indicative of its special character. 



I venture to assert there is not a single new character 

 assigned in Prof. Leidy's definition of the genus ^^ Quadrula " 

 (or, to use an expression of ills, Diflugia symmetrica " under- 

 Ann. & Mag. N. Hist. Ser. 5. Vol xvi. 23 



