56 MATTHEW ON OEGANISMS 



OEEATIOCAEIS, McCoy. 



A species of this geuus, or of Phinocaris, Clarke, remarkable for its small size, occurs 

 with the fish remains above described. 



Ceratiocabis pusillus, n. sp. (Plate IV, fig. 9.) 



Carapace. — Obloug, somewhat wider in front than behind. Back arched upward at 

 the anterior end, straight behind ; beak bent downward from the line of the back, nearly 

 one-sixth of the length of the carapace, narrow and- sharp-pointed ; front margin of the 

 carapace gently rounded down to the ventral, which is moderately convex ; abruptly 

 rounded at the posteiior end below, and arching forward and upward joins the back 

 with a reversed curve, forming a distinct angle. 



Abdomen. — Having four joints exsert ; the joints are wider than long, and to the last 

 segment is joined a long slender telson, and slender stylelets of less length ; the needle-like 

 telson is as long as the carapace, exchisive of the rostrum. 



Length. — About 30 mm. ; width, 5 mm. Length of carapace, 15 mm. ; width, 5 mm. 

 Length of exsert part of the abdomen, 4 mm. ; width, 2 mm. Length of the telson, 13 mm. ; 

 width at the base, IJ mm. 



Horizon and Localily. — This little species occurs in myriads in the black fissile shales 

 of DiA^ 2 of the Silurian succession at Cunningham Brook, Westfield Station, N.B. 



This species is of interest partly on account of its antiquity and partly because of its 

 small size, as well as its peculiar form ; for in its narrow shield and long acuminate 

 rostrum it diflers from all others. 



Ceratiocaris has a number of representatives in the Lower Helderberg rocks, but the 

 greatest development of the geuus is in the Devonian system. The finding of a species 

 so low down as Div. 2 of Silurian series, which by its fauna appears to be of the age of 

 the Mayhill Sandstone, is therefore of some importance. 



BUNODELLA, n. gen. 



This I'orm until better known is referred to a group of crustaceans which includes 

 Hemiaspis and others, once referred to the Eurypteridge, but later by F. Smith made a 

 separate family, and now by A. S. Packard made a suborder under the name of 

 Sj/nxiphosura. As only one species is known, the description of the species will stand 

 for the genus. 



BUNODELLA HORRIDA, n. sp. (Plate IV, fig. 8.) 



Body. — Ovate-elongate, trilobed longitudinally. Only the head and thorax known. 



Cephalic shield. — Subtriangular with rounded angles. Composed of a glabella, fixed 

 cheeks and moveable (?) cheeks. Glabella broadly cylindrical and rounded in front ; it 

 occupies nearly half of the width of the head shield, and more than half of its length. 

 The fixed cheeks are expanded in front as in Asaphus ; attached to the outside of the 

 fixed cheeks are ear-shaped lateral lobes, defined by an impressed line, which appear to 



