65 



less than the width. The posterior glabellar furrows have their inner ex- 

 tremities about one-third of the whole width in from the outer margin and 

 scarcely one-third the length from the posterior margin. They curve 

 slightly forward and outward, and are distinctly impressed do^vn the 

 sides of the glabella to the dorsal furrows. There is a second pair of fur- 

 rows situated less than one-third the length in front of the posterior pair ; 

 they are shorter and not so distinct. Neck furrow narrow and rather 

 deeply sunk ; neck segment also narrow and well defined. Surface cov- 

 ered with small rounded or obtusely pointed tubercles from one-fifth to 

 one-fourth of a line in diameter at the base, and usually their own diameter 

 apart from each other although they are sometimes more closely arranged . 

 In certain conditions of preservation these tubercles appear to have an 

 aperture in the top, but this is due to the wearing away of the crust ex- 

 posing a central dot of the darker-coloured matrix with which the tuber- 

 cles are filled. The sides of the glabella are so much inflated that they 

 slightly overhaug the dorsal furrows. 



Length of the glabella 6J lines ; width 7J lines ; width of neck furrow 

 I of a line ; width of neck segment, 1 line. 



This species is allied to such forms as Angelini's S. Wegalini, S- con- 

 formis, and S- granulatus, but is distmct from them all South-west 

 Point ; Div. 4, A. G. . Richardson. 



Genus Lichas, Dalman. 



Fig. 22. 



Fig. 22. — Lichas Canadensis. ThePygidium. 



L. Canadensis, n. sp. — Pygidium nearly flat with three pairs of broad 

 foliate ribs, the extremities of which form six projecting subtriangular 

 denticulations around the margin. The axis is short, conical, scarcely 

 one-third the whole length of the pygidium, nearly as broad as it is long, 

 the apex broadly rounded and prominent, at the base gradually sloping 

 into the general surface, well-defined at the sides by the dorsal furrows 

 which do not run round the apex but are continued as a distinct groove 



