424 Description of a new Trilohite, 



natus it would appear that the presence or absence of a spine on 

 the neck segment is not always of specific importance and should 

 some of those from Keeseville turn out to have only a plain neck 

 segment we would not perhaps on that ground alone be author- 

 ized to constitute two species.* 



3. Mr. Bradley's new specimens also show that there are three 

 pairs of glabellar furrows, the anterior being represented by two 

 small indentations just in advance of the points where the ocular 

 ridges reach the glabella ; and further that the course of the 

 facial suture is the same as it is in C. striatus, (Emerich). The 

 pygidium is more obtusely rounded than is represented in our 

 Figure 2. 



As to the correctness of the generic reference of this species 

 it may be remarked that Barrande is of opinion that no less than 

 eleven of those which Angel in has figured under the genera 

 Solenopleura, Eryx^ Conocoryphe^ and Harpides should be placed 

 in Conocephalites. In this view of Barrande's, Angelin has con- 

 curred.f The genus has thus been greatly extended and judg- 

 ing from the form of the head (and more particularly of the 

 glabella) of Angelin's species G. hrachymetopus, C. liomelotopus 

 and C. canaliculatus I think we are perfectly justified in referring 

 this species to Conocephalites. The genus is most closely allied 

 to Calymene, having the same number of segments in the thorax 

 — the same number and arrangement of pieces in the head and 

 the same general form and lobation of the glabella, the differ- 

 ences between the genera consisting principally in certain char- 

 acters of the pleurae and hypostoma | to which may be added the 

 ocular ridge which although not a constant character in Cono- 

 cephalites may be regarded as of some generic value as it does 

 not occur at all in Calymene. I would also state that since ex- 

 amining Mr. Bradley's recent collection, I have been strongly 



* Compare the article, Sur Vexistence de lafaune primordiale dans la 

 chaine cantahriquCj par M. Casiano de Prado ; suivie de la Description 

 des fossiles, par MM. de Verneuil et Barrande. Bulletin Geol. Soc. 

 France, 2o Series, vol. xvii, p. 516, (1860). And also Barrande's Sys- 

 teme Silurien, plate 13. 



t See Barrande's " Parallele entre Us depots Siluriens de Boheme et de 

 Scandinavie, p. 19 ; and compare the tables on p. 17 and 35 of the same 

 work. See also Angelin's Palceontologia Scandinavica. 



t See Barrande, " Systeme Silurien du centre de la Boheme," p, 417- 

 419. 



