92 ROYAL SOCIETY OF CANADA 



of the neck rin<:^ — G. F. M.], three lateral fuiTOws on each side, of which 

 the posterior greatly exceed tin' aiilfrior in size. Occipital furrow- 

 strongly bent forward in the middle. Inner cheek with reticulate mark- 

 ings, outer cheek ornamented with small radiating stria' and scattered 

 tul)ercleH." 



Linnar^Hon adds that "the basal lobes of the glabella are almost 

 surrounded b}' furrows, owing to the backward turn of the posterior 

 furrow, and the forwanl bend of the occipital furrow ; he also says that 

 the glabella is somewhat drawn in in front of the basal furrows, and further 

 forward is of more equal breadth. The occipital ring is considerably 

 widened in the middle, owing to the forward bend of the furrow, above 

 referred to ; the furrow is quite shallow in the middle, but deeper toward 

 the sides. The cheeks are more than twice as wide as the glabella ; the 

 inner part is gently convex, to this succeeds a gently concave belt, whose 

 circumference is bent backward, not (so far as one can judge from the 

 accessible examples) forming any elevated edge. The ornamentation of 

 the inner part of the cheeks consists of a fine network of raised lines. 

 Near the dor.sal furrow there is, as with the blind Conocoryphes, a 

 tubercle from which runs out a somewhat coarse elevated line. From 

 this line proceeds in a radiating manner, especially forward, close, fine, 

 irregular elevated lines. Elsewhere ihe cheek is sparsely sprinkled with 

 small tubercles, which seem to be regularly arranged toward the margin 

 where they form a regular row. No ornamentation of the glabella can 

 be distinguished on examples preserved in slate, but on those in the 

 Andrarum limestone, the surface shows a very fine granulation, and 

 scattered tubercles, finer than those on the cheeks." 



"The above description departs considerably from Angelinas figure 

 of Harpides breviceps. This shows a very convex head-shield, with the 

 inner part of the cheek strongly elevated, and sharply marked ott' from 

 the other part. The elevated part which may be compared to a cornu- 

 copia is marked by a depression in front of the glabella. The tubercles 

 which have their place l)eside the dorsal furrow lie in depressions. A 

 part of the original examples preserved in the Eoyal Museum agree in 

 this respect nearly with the figure. Others again by transitional forms, 

 connect with much less convex examples, and serve to show that the 

 aforesaid turgidity is the cheek's inner part only gently arched, and it 

 passes by degrees into the outer concave part. In front of the glabella 

 one finds in these examples oidy an indication of a depression, which also 

 is a sinking beside the dorsal furrow that is quite insignificant. Ex- 

 amples preserved in slate are in all respects near to the above, and there- 

 fore I do not hesitate to refer them to Angelin's species." 



" With the exception of JI. breviceps, all the hitherto (1882) described 

 species belong to the base of the Lower Silurian System. 77. rugosus, 

 Sarsand Beck, occur in the Ceratopyge limestone [=Tromadoc] H. Grim- 



