﻿HOMALONOTUS. 



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edge. The pleura; are strongly granular, the granules taking the form of closely placed 

 squama) over the whole surface. 



On the tail the granules are rounder and less closely placed, but they cover the whole 

 surface. The shape of the tail is truly triangular, as wide as long, contracted near the 

 apex, and then pointed, the tip somewhat recurved. 1 The axis is rather narrow, and not 

 much distinguished from the sides, the furrows being quite continuous across. There 

 arc eight of them, the upper not stronger than the rest ; and all are deep furrows, only 

 rather less broad than the intervening ridges. They arch across the axis, which is only 

 slightly convex, and pass direct across the sides, which arc gibbous externally, but rather 

 flattened above. 



The eight furrows abruptly cease at rather beyond halfway down the tail : on the 

 sides they cease entirely; on the axis there are one or two faint ribs beyond them. The 

 incurved under margin of the tail is very remarkable. It is sharply incurved, strongly 

 concave, and roughly granular, and there is besides a strong lateral contraction about 

 halfway down the tail (see fig. 9). 



Localities. — Abundant in the Upper Ludlow Rocks of Shropshire, and all the border 

 counties ; also of Radnorshire, and other places in South Wales ; Llangollen, North 

 Wales ; Westmoreland, near Kendal, abundant ; and under the name of 77". rhinotropis 

 it occurs in Gothland. Dr. Honeyman has found it at Arisaig, Nova Scotia. 



H. ludensis, of Murchison, is now well understood to be a synonym ; s but nevertheless 

 there are two species in the Ludlow rocks, even in England. And to preserve this old 

 name, I beg to apply it to the very unpretending looking head, fig. 1 (lent to me by 

 Mr. H. W. Edgell, jun.). That species has not the tricuspid front of II. Knightii, but 

 a smooth regular contour to the margin; and is, indeed, more nearly like the II bisidcaius; 

 but I cannot be sure to what sub-genus it should be referred — possibly to Dipleura. 

 It may be shortly described as follows : 



HOMALONOTUS LUDENSIS, 71. Sp. PI. XII, fig. 1. 



(Not of Sil. Syst., pi. vii, figs. 3, 4, for which see H. Knightii.) 



H. capite transverso semicirculari convexo, glabella brevi distinctd, fronle concavd 

 subpland august d, genis modicis, oculis hand remotis, sulco cervicali jjerdisfincto. 



1 Angelin's figure docs not show this. Our figures 9 (and fig. 5, copied from the 'Silurian System') 

 shew it best. It is not very conspicuous. 



2 The original specimen of H. ludensis, ' Sil. Syst.,' pi. vii, fig. 3, was in the cabinet of the late Mr. J. 

 Evans. It is now in the Museum of the Worcestershire Nat. Hist. Society. 



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