﻿IIOMALONOTUS. 



Ml 



The tail is regularly convex, ten lines long by eleven broad ; its front margin greatly 

 arched, and the sides retreating at almost a right angle from the centre ; the axis broad, 

 conical, nearly reaching the end of the tail, its tip blunt and prominent ; it is marked by 

 eight or nine rings (ten in larger French specimens), and the furrows which separate these 

 are distinct though shallow, — several of the front ones showing a plane pseudo-articular 

 surface between the rings (this character is well shown in the foreign figures). 



The axal furrows of the tail are sharp, but shallow. The sides slope regularly outwards, 

 and have a very smooth appearance. They are scored by seven or eight narrow sharp 

 lines, which reach the sharply incurved margin and decussate it so strongly as to produce 

 sharp serratures, a character not observable, so far as I know, in any other species. The 

 incurved edge is very abrupt, but this is usual in the genus. 



H. Brongniarti is described by Rouault as having a slightly prominent glabella, 

 narrowed in front, and showing two lateral lobes ; and the tail with a shortened axis, 

 marked by ten ribs, and an equal number on the side-lobes. It is somewhat doubtful if 

 M. Rouault's be the true species, but ours is clearly the form described by Deslongs- 

 champs. The fossil quoted by De Verneuil from the Sierra Morena has a longer 

 and more triangular tail, with interlined ribs, and the head so figured has wider cheeks. 

 The two are nevertheless allied forms. 



Locality. — Lower Silurian pebbles, in New Red Sandstone ! at Budleigh-Salterton 

 Cliff, South Devon. 



Foreign localities. — May, Normandy ; also Gahard, near Rennes (Rouault), and 

 possibly Vitre (Rouault). 



HOMALONOTUS VlCARYI, U. Sf. PI. XIII, fig. 10. 



This small species, of which we have only the caudal portion, is quite distinct from 

 any other, and I wish to distinguish it by the name of the gentleman who has paid so 

 much attention to the fossils of the locality in which it is found. The shape is blunt- 

 triangular. There are seven nodular rings on the axis, and six ribs partly interlined 

 on the convex sides, the outer margin strongly incurved, the apex notched beneath. The 

 regular conical axis, distinct all round, resembles that of the //. Brongniarti, with which it 

 is found. But the smooth blunt incurved edge has none of the serrations seen in that 

 species, nor do the furrows quite reach the margin. It is, moreover, quite distinct from 

 the unnamed species in our PI. X, fig. 18. 



Locality. — Llandeilo (or Arenig ?) Rocks ; found in the pebbles of Budleigh 

 Salterton, South Devon : (cabinet of W. Vicary, Esq., who first drew attention to the 

 fossils of this remarkable pebble-bed, and has laboriously collected and investigated them, 

 thus adding to the British series a new fauna, which is identical with that of Normandy). 



