168 F. Schmidt and T. R. Jones on 



we are enabled to retain for this common species tlie name by 

 whicli it is best known, and that Avithout any evasion of the 

 rnles which liave been suggested for the preservation of zoolo- 

 gical peace. Dr. Gray and Prof. Perrier are shown to be 

 justified in their adoption of the specific term HchnideJiana for 

 ihe CaJcita discoideo.. (Lamk.) of Mlillcr and Troschel. 



Henceforward, however, those zoologists who add to the 

 specific name the name of its author must bear in mind that 

 Nicolaus Bruzelius claims to sliare with lletzius in some of 

 the earlier specific titles given to various bracliiatc Echino- 

 derms. 



XIX. — On some Silurian Leperditi^e. 

 By Fr. Schmidt and Eupert Jones. 



7h ihe Editors of the ' Annals and Mar/azine of 

 Natural Tlistory.'' 

 Gentlemen, 



M. Fr. Schmidt, of the Academy of Sciences, St. Peters- 

 burg, one of the relatively few palfeontologists who have 

 taken up the study of Lcperditiai and their allies, has favoured 

 me with the following ciiticisms on my " Notes on the Palae- 

 ozoic Bivalved Entoraostraca" *, published in the Ann. & 

 Mag. Nat. Hist. ser. 5, vol. viii. Nov. 1881. His long 

 and intimate acquaintance with these Entomostraca in Scan- 

 dinavia and llussia makes his opinion of great value, especi- 

 ally in the comparison of the English with the North-European 

 species, and of these latter among themselves. M. Schmidt 

 writes thus : — 



" 1. You regard Leperditia halthica'\ (His.) and L. Histn- 

 ffert, Schmidt, as varieties or sexual forms ; but they belong 

 to diflferent geological horizons, as shown in my mcmoirj, 

 and there is a striking specific difterence between them in the 

 strong transverse striation on the inverted plate of the left 

 valve of the true L. halfhica, as shown in your pi. vi. figs. 4 h, 

 5 b, Ann. & Mag. Nat. Hist. 1856, and ])reviously noticed by 

 Hisinger and Kcyserling. The inverted plate of L. Tlisin- 

 rjeri is quite smooth. This latter species belongs to the 

 lowest part of the Upper-Silurian series of Gothland — that is, 



* These "Notes," marked "XII.," should be "XIII."; and the 

 '•Notes" marked "XIII.," in Ann. & Mag. Nat. Hist. September 1870, 

 should be "XII." 



t See Ann. & Mag. Nat. Hist. November 1881, p. 834. xM. Fr. 

 Schmidt and others adopt the term baltica ; but I prefer the Linutean 

 form of the word, as in " Tellina htlthica.'" — T. R. J. 



X Ueber die russischeu silur. Leperd. 4to, 1873. 



