New Species of Possits. 301 



its annulations horizontal, subparallel and nearly straight, 

 but faintly sinuous at their margins, both in front and 

 behind. Pleura? also decreasing very gradually in breadth 

 to the posterior end of the thorax, nearly straight and ter- 

 minating externally on each side in a long and very slender 

 spine, which is bent backward and outward at an angle of 

 about 57°. The spines increase gradually in length pos- 

 teriorly, the two spines on the anterior thoracic segment 

 being shorter than the pleura? from which they proceed, 

 and nearly equal in length to the genal spines immediately 

 in front of them, whereas in the posterior thoracic segment 

 the pleural spines are nearly three times as long as the 

 pleura? and as the spines on the pleurce of the anterior 

 thoracic segment. 



Pygidium broad and short, its outer margin broadly 

 rounded and fringed with spines, its inner or anterior mar- 

 gin almost straight and nearly three times as broad as the 

 length of the non spinose portion along the median line ; 

 its axis moderately convex and its pleura? flat. Axis nar- 

 rowly rounded posteriorly and terminating just within the ■ 

 margin of the pygidium, apparently bearing two transverse 

 annulations, the posterior unarmed and the anterior bear- 

 ing a long and very slender primary spine on each of its 

 rounded postero-lateral angles. These primary spines, 

 whose length considerably exceeds that of the united pygi- 

 dium and thorax, diverge for the greater part of their 

 length at an angle of about 48°, but curve slightly inward 

 at their outer ends. Outer margin of the pygidium armed 

 with four secondary internal spines between the two prim- 

 aries and with five secondary external spines on each side 

 of the latter. The four secondary internal spines are mo- 

 derately close together, nearly equal in length and about 

 one fourth as long as the primaries. The five outer secon- 

 dary spines on each side are much closer together than the 

 four inner ones and not more than one half as long. 



Surface markings unknown. 



Long Point, at the northeast angle of Lake Winnipegosis, 



