164 



divided into two almost equal parts by a strong double eye-line, 

 or ocular ridge, proceeding diagonally across them from the 

 third glabella pit, on each side. Facial sature cutting 

 the posterior margin far out ; posterior margin of the free 

 cheeks broad like the neck segment. Thorax unknown. 

 Free cheeks small, elongately triangular, with a strong broad 

 striate border, and a similar long genal spine ; surface 

 granular ; eye large, semilunar. 



Ohs. An entire head shield of C. Stephensi is not present in 

 the Collection, all that is usually seen being the glabella and 

 fixed cheeks. The position of the eyes is, hovs^ever, apparent, 

 just at the termination of the ocular ridge, a point where the 

 shield is always broken away. 



The abrupt termination of the short glabella grooves, 

 especially the two basal ones, width of the fore cheek, and 

 presence of the ocular ridge, are characters which clearly 

 separate our fossil from DiJcelocephalus ; neither is it 

 a Lonchocephalus, from the absence of the backward cervical 

 spine, shape of the glabella, and increased number of furrows 

 on the latter. G. Stephensi has many of the characters of 

 Conocephalites, as defined by Hall, but I have already pointed 

 out how this definition departs from that of M. Barrande, and 

 other well-known writers. C. Stephensi in no way possesses 

 the facial suture of Bathyurus or Bathyurellus, whilst it 

 has glabella furrows, which would entirely separate it 

 from the former, and partly from the latter. Barrande 

 has remarked on the resemblance of Conocephalites to 

 Cyhele in some of its features. The expanding 

 glabella pit-like furrows at the sides, diagonal eye 

 line, prominent front margin, and large fixed cheeks of 

 C. Stephensi appear to bear out this view. The present 

 species is quite distinct from either of the typical European 

 Conocephalites, and so far as I can gather, from any of the 

 American forms referred to this genus. At the same time, it 

 must not be forgotten that we are dealing with casts of the 

 interior, from which the crust has been removed ; and, there- 

 fore, some allowance has to be made in defining the various 

 proportions of the parts described. The axal furrows of the 

 head do not appear to be anything like so deep as in the 

 European species, or even so broad, neither is there any trace 

 of a cervical principle in C. Stephensi. It approaches nearest 

 to C. striatus, Emmrich* in which the eyes are widely 

 separated, and the ocular ridges present, but there is a 

 great difference between the two species in the form of the 

 glabella, and its grooves. Equally distinct are G. Sulzeri^ 

 Schl.f and C. coronatus, Barr.J the position of the 



* See Barrande, Syst. Sil. Boheme, I. Atlas, pi. 14, Figs. 1—7. 

 t Ibid, pi. 14, F. 8-23. t IMa, pi. 13, F. 20-26. 



