OF SILUEIAN AND DEVONIAN. 57 



have been movable. The eyes are uukuown, and no articulation between the thorax 

 and head shield has been observed. 



The thorax has seven segments preserved, and consisted of an elongate cylindro- 

 conical body, having triangular lappets or plenrœ attached at the sides. The abdomen, or 

 terminal extremity of the body, is iiukuown. 



Sculpture. — The axis of the body is covered everywhere with a rough coating which 

 appears to consist of minute appressed spines, directed backward ; these obscure the 

 articulations so that the segmentation of the body is seen only in the pleurœ ; these little 

 spines are seen also on the fixed cheek and the front of the head ; this hirsute covering 

 is not found on the pleurae, nor on the moveable (?) cheeks. 



Ze«g'//i of the parts iDreserved, 30 mm.; width, 18 mm. Length of cephalic shield 

 from the basal sinus, 10 mm. ; width, 18 mm. Length of thorax, 20 mm. ; width of 

 anterior end, 18 mm. ; or posterior end, 10 mm. 



Horizon and Localily. — In the black lissilc shales of No. 2 of the Silurian, near "West- 

 field Station, N.B., in company with Diplaspis Acudica and Ceratiocaris pusiilus. 



The three anterior pleurse, which are defective in the example figured, have been 

 restored as if they were of the same form as the posterior ones. They may, however, 

 have approached more nearly in form to the movable (?) cheeks (or lateral lobes) of the 

 cephalic shield. 



The genus may be compared to Bunodes, Eichwald, in the tuberculated surface, and 

 the peculiarities of the lateral appendages of the carapace ; for although no pleural grooves 

 have been observed, these appendages are so set as to overlap, in an imbricate manner, 

 the back of each pleura overlapping the front edge of the one behind it. But Bunodes 

 differs from this genus in having a larger cephalic shield, and in having one segment 

 less in the thorax ; the three parts of the body are also more distinct. In the smaller 

 head and the triangular pleurse our species resembles Exapinurus, Nieszk, rather than 

 Bunodes proper, but cannot well be compared in other respects. Were it not for the 

 peculiar form of the head, the separate jîleurce and the obscure segmentation of the axis, 

 our genus might be compared with Pseudoniscus, Neiszk, which it resembles in general 

 outline and in the regular tapering of the posterior part of the body. 



In addition to the above species there occur with these fish-plates a few examples of 

 a peculiar organism apparently related to the graptolites. It consists of a rather thick 

 rod apparently having cells along its sides, and the orifices of these cells have long spinous 

 processes attached to them. An example of this fossil has been sent to Prof Charles 

 Lapworth, but no report of its nature has been received. 



B. — Organisms of the Devonian System. 



These are three : the wing of an orthopterous insect, a chitenous grub, and a peculiar 

 little crustacean. The first organism may be described under the name of 



G-ERONETJRA WiLSONi, n. gen. et sp. (Plate IV, fig. 10.) 



The anterior wing of the body (the only part known) is elliptical elongate, the 

 venation strongly marked and the scapular ridge conspicuous. 



Sec. IV, 1888. 8. 



