﻿88 



BRITISH CARBONIFEROUS BRACHIOPODA. 



admitted his mistake. Professor Phillips describes his shell as follows : " Orbicular ; no 

 mesial fold ; ridges equal, rounded, radiating." This diagnosis will agree with many of the 

 specimens, but the peculiarity presented by the central rib and corresponding sulcus in 

 the opposite valve are characters not to be overlooked, as well as the small triangular 

 area which is not represented in the figures of the shell given in the • Geology of York- 

 shire.' In England, B. radialis has been obtained from the Carboniferous limestone of 

 Bolland, also by Mr. Burrow in the lower scar limestone of Settle, Yorkshire ; and 

 Professor M'Coy mentions it from Derbyshire. In Ireland it was found, according to 

 Mr. Kelly, at Bruckless, Malahide, and Millecent, in the Carboniferous limestone and 

 calcareous slate. In Scotland it has been discovered near Lesmahago by Dr. Sliman. 

 In Belgium it has been collected at Vise and Ton may by Professor de Koninck ; and by 

 the authors of the e Geology of Russia ' in the Carboniferous limestone of Zaraisk, in the 

 government of Riaisan, Russia. 



Retzia ulotrix, De Koninck. Plate XVIII, figs. 14, 15. 



Terebuatula (crispata) ulotrix, De Koninck. Animaux fossiles de la Belgique, p. 292, 



pi. xix, fig. 5, 1843. 



Spec. Char. Somewhat circular or slightly transverse ; moderately convex, without 

 fold or sinus ; each valve is ornamented with from seven to nine angular ribs, of which 

 the three central ones are the largest and most prominent ; the beak of the ventral valve 

 is somewhat produced, straight, but slightly incurved, and truncated by a small circular 

 foramen, a flattened triangular area existing between it and the hinge-line. Shell-struc- 

 ture punctate. Interiorly there exists two spiral appendages, with their extremities 

 directed outwards for the support of the oral arms. 



Dimensions variable ; two British examples have measured — 



Length 6, width 6, depth 3 lines. 

 9 91 1 



j> *>i >> 3' »» " 



06s. This little Retzia was first described by Professor de Koninck under the desig- 

 nation of T. crispata, but in the explanation of his plate the name was altered to that of 

 T. ulotrix, from the author having found that the first denomination had been already 

 employed. I am acquainted with only two English examples of this shell, one, from 

 Bolland, I found in the British Museum ; the other, from the Carboniferous limestone 

 of Wetton, in Derbyshire, is in the Museum of Practical Geology ; and upon sending 

 drawings to Professor de Koninck, I was assured that they were referable to his species. 

 This shell is stated to be likewise very rare in Belgium, and is found in the Carboniferous 

 limestone of Tournay, where it would appear to have attained somewhat larger dimensions, 

 the specimen figured by Professor de Koninck measuring — 



Length 6^, width l\ t depth 4 lines. 



