122 FOSSIL ESTHERItE. 



evidently varies very much, being sometimes obsolete ; indeed, at first I thought to class 

 it with Cytheropsis (see above, p. 38, note). 



Beyricliia Pyrrha is very abundant in the greyish marl of the Permian formation 

 near Burakova, in the government of Kazan, and occurs here in company with JEstheria 

 exigua {Cytherina Eos, Eichw.), see pp. 38 and 40. 



In treating of the following Entomostraca I have much hesitation in assigning them 

 to definite genera and species, as their hinge-lines and other specialities are, for the most 

 part, unknown. Figs. 13 to 15, 20 to 25, and figs. 31 to 34 may be either CytJieres, Cyprides, 

 or CandoncB, and there are but few distinctive features among them, whether they be of 

 Carboniferous age (figs. 13, 14, 15), of Rhsetic (figs. 20 — 24), of Jurassic (fig. 25), or 

 of Wealden (figs. 31 — 34) ; amongst these last, tangible diff'erences are best seen. 

 Comparing figs. 13 and 14 with figs. 20 and 21, we see similar-looking carapace-valves 

 from the Coal-measures of England and the Lower Mesozoic deposits of Virginia ; and, 

 allowing for the possible effects of pressure and imperfection of the margins of the 

 valves, it is somewhat hazardous to attempt to define their specific characters. A glance 

 at Plate I and Plate IV of my ' Monograph of the Tertiary Entomostraca of England,' 

 1856, will give an idea of the recent and tertiary forms that most closely resemble those 

 under consideration. Among those referred to, however, Candona (of freshwater habitat) 

 is the genus which supplies the chief analogies ; and as the habitats of EsthericB seem to 

 me to have been mostly freshwater, the associated fossil CypridcB may be provisionally 

 referred to Candona. I do not, however, deny that some of them may have been 

 Cytheres (but even then they may have affected fresh or brackish water) ; nor that, being 

 Candona, they may not have been able to live in saltish water (as CypridcB do occa- 

 sionally, see above, p. 8). 



The following CypridcB are figured with what appears to be the anterior extremity 

 upwards ; and the more convex of the two long margins is regarded as the dorsal. 



3. Candona (?) Salteriana, sp. nov. PI. V, figs. 13, 14. 



Length, -^ inch. Breadth, -^L inch. 



Carapace- valve smooth, elongate- oval, with nearly straight ventral and dorsal margins. 

 Pig. 13 has both extremities somewhat obliquely curved; fig. 14 has one end nearly 

 semicircular ; and this was probably the natural condition, as is usual in this group. The 

 antero-dorsal slope in fig. 14 may have been exaggerated by pressure. This Cyprid is, 

 in size, intermediate between Candona Forbesii and C. BicJiardsoni of the Eocene deposits 

 (' Tert. Entom.,' p. 18, pi. 4, figs. 8 — '12). Although little is known about it, yet it is 

 advisable to give it a distinguishing name ; and none can be better than one derived from 



