60 ROYAL SOCIETY OF CANADA 



OliYCTOCEPlIALUS, Wulcott. 



Oryctocephalts Wai.keki n. sj». (l'I. II !.. Hi^. 2.}. 



Outline without the moviible cheeks sub-ovul, with them parabolic. 



Jlead-shield broadly semicircular. Middle piece sub quadrate. An- 

 terior marginal rim narrow. (Glabella broad and club sha])cd, marked 

 by three pairs of circular, shallow pits in place of glabellar furrows ; the 

 two posterior pits connected by a shallow, arched furrow, and the pits on 

 each side of the glabella connected by a shallow depression, parallel to 

 the axis of the glabella ; there is a pair of small pits at the anterior 

 angles of the glabella indicating a fourth pair of furrows. The dorsal 

 furrows are deep at the front and sides. The rixed cheek has a narrow 

 area in front of the ocular fillet, and behind the fillet is triangular, and 

 at the back nearly as wide :is the glabella ; the eye-lob'j is narrow and 

 reaches nearly to the ])osierior marginal furrow ; inside the eye-lobe and 

 ocular fillet, which is pi-orainent is a shallow furrow that nearly connects 

 with the jiosterioi- marginal furrow. The posterior furrow and fold are 

 nan'ow and distinct. The occipital ring has a moderate breadth and a 

 well marked furrow. 



The movable cheeks are narrow and carry long spreading spines, 

 which reach as far back as the middle of the pygidium ; the points of the 

 genal spines are as far apart as the body is long. The area of the cheek 

 is twice as wide as the marginal fold, and the genal spines are twice as 

 long as the cheek. 



An individual 4^ mm. long has apparently 6 joints (possibly 7) in the 

 thorax ; one of 10 mm. has at least the same number. The pleurœ are 

 flat and have oblique furrows, and are abruptly bent backward at the end, 

 where each bears a slender spine, that on the Uth (or last ?) segment 

 being somewhat longer than the others, and is about one and a half times 

 the lengtii of the body of the pleura. 



The j)ygidium is only known from an individual 4^ mm. long, in which 

 the line of division between the tail-shield and the body segments is not 

 clearly shown. Assuming that the thorax has six joints, there are five 

 somites in the jjygidium, which has five oblique furrows, the posterior 

 ones being bent more and more backward, toward the rachis. The 

 rachis is separated by about one-third or one-quarter of its length from 

 the ])08terior margin. There appear to be weak spines around the 

 margin. 



Sculpture. — The surface appear:» to be minutely punctate. 



Size. — The largest head observed indicates a length for the whole 

 body of 14 mm. AVidth at the genal angles, 11 mm. Width of middle 

 piece of the head shield, 8 mm. 



