338 Prof. T. R. Jones on 
Dr. H. B. Holl, F.G.S., and will be deposited in the British 
Museum. 
This cast somewhat resembles in outline the perfect valve, 
fig. 2,a; but it has a relatively shorter hinge-line and a fuller 
antero-ventral curve, by which differences it approaches 
L. Hisingert, without, however, identifying itself with that 
form. Although it has also some resemblance to ZL. anti- 
costiana (fig. 8, a) in size and shape, this cast may belong to 
the same variety of ZL. balthica as fig. 2, namely var. 
contracta. 
Pl. XIX. fig. 13. The outline of a small right (overlapping) 
valve, centrally convex, 3) inch long. It is in the white 
Upper-Silurian Pentamerus-limestone of Talkof, Livonia, with 
Primitie * and Obolus (?), and was communicated some years 
ago by the late M. d’Hichwald. This is very much like 
Schmidt’s fig. 22, already referred to; but its postero-dorsal 
angle is more, and its front angle less, pronounced, thus 
making its main diameter (diagonal) less oblique than in that 
variety of L. Hisingert, Schmidt, and giving an outline far 
more like that of our fig. 2 a, though still fuller on the ven- 
tral curve. Thus it seems to be a minute individual of 
L. balthica, var. contracta. 
PL. XIX. fig. 14. The imperfect outline of a partly-imbedded 
very small right valve, with eye-tubercle and muscle-spot. 
Length 5 inch. In this minute specimen we have the long 
hinge-line of the large L. balthica, together with the typical 
dorsal angles fore and aft. In a dark-grey compact ‘‘Pen- 
tamerus-limestone’’ from Kamenetz-Podolsk, on the river 
Zhbroutsch. Communicated by the late M. d’Hichwald, and 
labelled “Z. phaseolus, His.;” but the shape is against this 
allocation. ‘The limestone contains other small Entomostraca 
besides this dwarfish var. contracta of L. balthica. 
Pl. XIX. fig. 17. This is a small left valve in grey lime- 
stone, also communicated by M. d’Hichwald, probably from 
the Baltic provinces ; but the label has been lost. It measures 
74; inch in length, and has the contour of the long-backed 
oblong type of L. balthica as far as can be seen, its postero- 
ventral margin being still imbedded in the limestone. The 
ocular tubercle is visible; but the muscle-spot has been lost 
by fracture of the convex centre. 
Fig. 17 much resembles the cast, fig. 3, but is larger, 
in the proportion of 8:6 in length, and has a more 
decided postero-dorsal angle. It agrees with L. balthica, var. 
contracta. 
* Labelled “ Leperditia minuta, Kichw.,” and very near to P. concinna. 
