400 Albany Museum Records. 



Width between base of genal spine and outei* lower margin of eye, 

 1.2 cm. 



Thorax. Eight segments shown in type, ten in a second speci- 

 men, nine in a third. Segments in the axis formed by a narrow 

 prominent semi-circular ring, bearing a prominent spine : in front 

 there is a scoop-shaped portion which articulates with the seg- 

 ment in front. The prominent rings expand near the margin of 

 the axis, and on the sides first bend horizontally outwards and 

 then curve steeply downwards. The convex axial ring divides on 

 the sides into two portions, separated by a deep groove, the hinder 

 portion more swollen than the one in front ; in rolling up, the 

 front half of tUe pleura slides under the swollen back portion of 

 the pleura in front. When a rolled up specimen is viewed from 

 the side, it looks as if the sides were formed only by the swollen 

 back portions of the pleurae. The triangular portion of the front 

 part of the pleun^, which is then visible, has the appearance of 

 being a scale ovei-lapping the segment in front, as Salter's drafts- 

 man actually depicted in PI. XXV., fig. 9c., and even Lake's drafts- 

 man PI. XXIV., fig. 10b, shows the same thing ; but when a speci- 

 men that is not rolled up is studied, there is no sign of the pro- 

 jecting scale. 



The specimens are too fragmentary to give dimensions, but the 

 longest spine in the type is 7 mm. long, measured from the base 

 to the tip. 



Cat. No. 2121, Type, No locality or donor given in catalogue. 



