94 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Table 16. — Measurements of Cyrolexis haquei from the Lower Productus 



Limestone 



Measurements, in millimeters 



142064 c.15.0 14.2 12.4 



sent. Tschernyschev's drawings (p. 96, fig. 31-35) show that the in- 

 ternal structures are nearly identical to those of C. haquei. The other 

 species are assigned to Cyrolexis only tentatively because no specimens 

 were examined directly. However, Tschernyschev's descriptions are 

 clear and his illustrations are so good that the others may be assigned 

 with little doubt. 



C. haquei most nearly resembles C. waageni (Netschajev, 1894) 

 from the Upper Productus Limestone of the Salt Range. It differs 

 only slightly from that species, in its less strongly convex pedicle valve 

 with narrower, slightly more attenuate beak, greater number of costae 

 on the fold, normally fewer costae on each flank, and its somewhat 

 more strongly convex brachial valve. Many specimens of C. haquei 

 are proportionately wider than is typical for C. waageni, but others 

 have the same dimensions as that species. The fold on some specimens 

 of C. haquei is lower and broader, although this feature also is vari- 

 able and not a clear distinction from C. waageni. 



Netschajev (1894) cited Waagen's (1883) specimens of C. super- 

 stes (Verneuil) as examples of Camarophoria waageni. These are 

 compared above to C. haquei. He illustrated (Netschajev, 1894, pi. 5, 

 fig. 10) a specimen from the Russian Permian near Atary which, 

 while probably belonging to a species of Cyrolexis, is greatly different 

 from either of the two Salt Range species. It is more strongly and more 

 completely costate, less globose and proportionately longer. The draw- 

 ings probably are approximate, so Netschajev's specimens may have 

 resembled the Salt Range species more closely than shown. 



Occurrence and abundance. — Lower Productus Limestone, Rukhla 

 area, Salt Range, Pakistan (19 specimens USNM 142068). 



Age. — Lower Permian. 



