﻿IIOMALONOTUS. 



103 



Calymene? Daviesii, n.sp. Fig. 23 (Woodcut). 



Fig. 23. 



C. caudd lata snbtrigond ', depressd, antice subrecfd, postice rectanguld : axe angusto 

 longo, §-annulato, pcrcurrente ; lateribus 1-costatis-costis radiatis, valde duplicatis : sulcis 

 prof undis, fascia caudali angustd convexd. Lat. \\ unc. Long. 1 unc. 



The general character of this carious specimen forbids us to associate it with any 

 other genus, as it is unlike the usual Upper Silurian forms. 



The tail is much depressed for the genus, wide, and 

 rectangular behind, the sides very little curved, the apex 

 obtuse. The length is rather more than two thirds the 

 width, which is 1^ inch ; the axis occupies only one 

 fourth of the whole width, and is regularly conical, convex, 

 and reaching the very end of the tail. It has eight 

 distinct rings and a short terminal portion. The axal 

 furrows are strong, the side-lobes convex along the middle, 

 but not towards the margin, which is only slightly decurved. There are seven distinct 

 lateral ribs reaching almost to the margin, and strongly duplicated throughout. The 

 direction of the ribs is outwards, not much backward. The specimen is only an interior 

 cast, and the actual margin is not seen. But the caudal or subcaudal fascia is very 

 distinct, convex, and narrow all round, and the furrows, both of the axis and the 

 sides, are strong and deep. The fulcral point is so remote, that if, after all, this should 

 prove to be an unusual form of Phacops, I should not be greatly surprised. Still I 

 think it is a Calymene. 



Locality. — Wenlock Shale of Glan Wye, 3 m. N.W. of Builth, in Radnorshire. 

 (Cabinet of Griffith Davies, Esq., of Islington.) 



C. ? Daviesii, from the Wenlock Shale- 



Homalonotus, Kdnig. 

 Dipleura, Trimerus, Green, &c. 



A natural genus, which has been admitted by every writer on Trilobites, since our old 

 friend Dr. Konig gave us the figure in the ' Icones Sectiles.' 



There is no pretence for separating any of the forms except as convenient subgenera. 

 From Calymene, its near ally, as, indeed, from most Trilobites, it is distinguished at once 

 by its want of distinct trilobation ; and this peculiarity is only less distinct, not absent, 

 in the earlier species. In the characters of the thorax, eyes, labrum, and even in the 

 contour of the tail, the resemblance is so close to Calymene that it is often difficult to 

 distinguish fragments of one genus from the other. In general, the very obscure glabella, 

 scarcely lobed ; and the broad, highly convex, and slightly trilobate thorax, distin- 

 guish it. 



