A CARBONIFEROUS FAUNA FROM NOWAJA SEMLJA. 167 



but in the present case, what is left of the shell in the cardinal region is more in 

 favour of Dr Thomas' explanation.* 



The depressed shape of this shell gives it a greater resemblance to the form referred 

 by Semenow and Moller to " Orthis striatula " than to any other Schizophoria, but 

 in the Nowaja Semlja shell the hinge-line is shorter, t 



Production. 



Genus Chonetes Fischer de Waldheim. 



Chonetes papilionacea (Phillips). (PL IJ. fig. 25.) 

 Davidson, loc. cit., pi. xxxv. figs. 3-5. 



The Cape Cherney form is undistinguishable from the flatter variety of the British 

 Chonetes papilionacea. 



Dr T. F. Sibly has recently remarked that the term papilionacea embraces more 

 than one form, and for the flat kind — as is the present one — he proposed the new name 

 " compressa," a name very expressive of the general appearance of the shell, but 

 unfortunately already applied to another species of Chonetes.% 



Chonetes (sp. plur. ?) (PL II., figs. 26-28a.) 



Numerous specimens of all sizes up to 12 mm. belong to one or more species, the 

 general characters of which are as follows : — The shape is more or less semicircular, and 

 the pedicle-valve evenly convex, but rather shallow ; the brachial valve is very concave, 

 so that there is little space between it and the brachial one. The ribs increase by 

 forking, but do not number more than about forty, on the larger specimens. Owing to 

 the fragmentary condition of the material an accurate determination cannot be given, 

 but it may be indicated here that where the shell's width does not exceed its length, 

 and the shell is ornamented by few ribs, it bears a certain resemblance to the Devonian 

 Chonetes armata (Bouchard), as figured by de Koninck,§ whilst the more transverse 

 ones, with more numerous ribs, appear identical with the form provisionally described 

 as Chonetes cf. crassistria by Dr A. Vaughan.|| 



A third type is represented by a specimen more globose than the above, with a com- 

 paratively low area, as obtains, for instance, in Chonetes minuta (Goldfuss), from which 

 it differs in the nature of its ribbing. IT 



* J. W. Salter, " Note on the Fossils from the Budleigh Salterton Pebble-Bed," Quart. Jour. Geol. Soc, 1864, 

 p. 295, pi. xvii. fig. 8 ; Davidson, Brachiopoda of the Budleigh Salterton Pebble-Bed, Pal. Soc. 1881, pi. xli. fig. 11. 



t " Uberdie oberen devonischen Schichten des Mittleren Russlands," von P. Semenow und V. von Moller, Bull. 

 Acad. Imp. Sciences, St Pe'tersbourg, 1863, p. 691, pi. ii. fig. 10. 



| Waauen, Pal. Indica : Salt Range Fossils, 1884, iv. p. 630 ; T. F. Sibly, " On the Faunal Succession in the 

 Carboniferous Limestone of the Midland Area," Quart. Jour. Geol. Soc, 1908, p. 78, pi. i. fig. 7. 



§ Monographic des Genres Productus et Chonetes, 1847, pi. xx. fig. 14. 



|| " Palaeontological Sequence in the Bristol Area," Quart. Jour. Geol. Soc, 1905, p. 294, pi. xxvi. fig. 2. 



IT As interpreted by de Koninck, loc. cit., fig. 18. 

 TRANS. ROY. SOC. EDIN, VOL. XLVII. PART I. (NO. 7). 25 



