﻿242 BRITISH FOSSIL CRUSTACEA. 



posterior angles of the cephalic shield are produced into long spines, as in the preceding 

 species, three tenths of an inch in length, slightly curved, and spreading out on either 

 side from the body. Thoracic rings five, which, as in the preceding species, decrease in 

 breadth towards the posterior extremity; the lateral lobes, extending in a straight line, 

 terminate in a short spine, and having an angular furrow, which proceeds to the end, 

 curving at the same angle to the point of each spine. Caudal extremity small, with two 

 or three radiating divisions, to which is appended a spine about equal in length to the 

 head and body. 



"This Crustacean differs from the preceding one in having much shorter spiny 

 terminations to the pleurae and a much shorter tail-spine. The detached head or 

 cephalic shield is more orbicular, and the arched rings proceeding from the middle 

 portion of the head (glabella) terminate on each side in short spines, a character not 

 observed in any of the specimens of B. Beyinee. I have not succeeded in obtaining 

 good specimens of this species with the body and tail entire ; an imperfect one forms the 

 centre of a concretion in the shale, and exhibits a portion of the body with the tail-spine 

 uncompressed, showing distinctly the division of each thoracic ring, with its grooved 

 lateral angles as in the Trilobites. In another specimen, which was accidentally relieved 

 from the shale, exposing both sides, the body was found to be doubled back upon the 

 head, like an Ampyx or Trinucleus. This species is allied to Bellimtrus bellulus, Konig, 

 but differs from it in the more orbicular form of the head, the spring termination of the 

 pleurae, and the greater proportion of the body to the cephalic shield. 

 " The following are the measurements of fig. 2 : 



Total length . . . .1 inch or 25 mill. 



Total breadth . . . .11 lines ,, 22 „ 



Length of body . . . 7 „ „ 15 „ 



Breadth of cephalic shield . . 8 ,, „ 17 ,, 



Length of cephalic shield . . . 4 ,, ,, 8 „ 



,, telson, about . . -2 mcn » -^ ,, 



Locality. — Pound with the previous species at Bilboa Colliery, Queen's County. 

 Mr. Baily makes the following observations on the beds in which Bellinurus occurs : 

 " As to the question of the freshwater or marine habitat of these Crustacea and their 

 associated fossils, I am inclined to the opinion that the deposits in which they occur were 

 of freshwater or estuary origin, from the abundance of small shells like TJnio, and others 

 very similar to the freshwater Mytilus (Breissena) polymorphus, accompanied by the 

 remains of succulent or marshy plants. This opinion corresponds with the observations 

 of Martin and Prestwich. Other theories have been advanced attributing a general 

 marine origin to the coal-beds, in support of which great stress has been laid upon the 

 fact of the occurrence of minute spiral bodies found attached to some of the plant- 

 remains, and formerly referred to Spirorbis, a marine genus of Annelida common upon 



