336 Notes on New Species 



which this figure was taken, my father describes the frus- 

 tule as " excessively thin, in front view quadrangular," and 

 does not even suggest a comparison with B. Baileyii, Sm. 

 The descriptions, however, closely correspond, and I can 

 discover no good reason for their separation. 



It will be seen, by reference to the plate, that no less 

 than five forms of Biddulphia are represented, each with 

 more or less of resemblance to the others. Fig. 25 very 

 closely corresponds to the figure and description of Zygoce- 

 ros 31obiliensis, (Bail. Mic. Contrib. Plate 2, Fig. 34,) while 

 Fig. 34 of the present plate corresponds closely with Fig. 

 ^5 of the JNIicroscopical Contributions, differing only in 

 having one spine instead of two. But the other spine is 

 again present in Figs. 35 and 69, while in Figs. 66 and 

 68, which he assigns to Zygoceros occidentalism no spines 

 whatever are apparent. As the Z. Mubiliensis was pub- 

 lished in 1850, and the above not drawn until 1854, it is a 

 little singular that the resemblance should not have been 

 noticed. My father certainly did not regard the number of 

 spines as of specific importance, as he assigns the same 

 name of " trinacria " to both Figs. 34 and 35. To Fig. 66 

 he assigns the specific name of " occidentalism I cannot, 

 however, discover from the original objects any essential 

 difference in structure, and am inclined to think that the 

 number of the Opines is not of specific importance. I re- 

 gard all the forms, therefore, above alluded to, as varieties 

 of Biddulphia Baileyii, Sm. There is great difference in 

 size, it is true, between these forms, but intermediate sizes 

 are not uncommon. 



Fig. 26. EuNOTiA ANisoDON, Bail., nov. sp. Large ; 

 venter concave ; dorsum convex, with two ridges sym- 

 metrically arranged, with the dorsum of each ridge com- 

 posed of three subordinate ridges ; ends produced and 

 broadly rounded ; strisB minute, converging slightly. 



Hab. Para River. 



