CYPHASP1S. 19 



ever, while coming nearer to Sandberger's and probably being more correct, retains 

 the distinctive features of Goldfuss's; the overhanging glabella, the forward eye, 

 and, most of all, the little pit just inside the latero-posterior angle of the cheek, to 

 which both he and Goldfuss draw particular attention. He states his figure to be 

 a restoration from several poor specimens. From our species it differs in the 

 before-mentioned particulars. Coming to Romer's G. hydrocejohala, we find better 

 figures given by himself in his ' Beitrage,' pt. 3, p. 7, PI. 16, fig. 11, and by 

 Kayser, 1 than the original one which is quoted by Sandberger, and these show that 

 it has altogether a wider head with a differently shaped cheek, a wider and more 

 rounded glabella, and other differences ; and Kayser strongly insists that it is 

 distinct. He, on the other hand, unites with it a Bohemian form, C. clavifrons, 

 Barr. 2 (not Dalm. nor Burm.), ultimately united by Barrande with G. Barrandei 3 

 Corda. This differs from our species in having the glabella much more over- 

 hanging the front border, the space in front of it more perpendicular, and the 

 cheek-spines much longer. The other species given by Romer in his ' Beitrage ' 

 are very different from the English one. 



In G. Hallii, Barr., 4 the glabella is shorter, the head is smooth, and the eyes 

 more sessile. In G. Cerberus, Barr., 5 and G. Davidsoni* Barr., the border of the head 

 is toothed. C. convexa, 1 Barr., is a narrower and less elevated form, and this is still 

 more the case in G. humillima, Barr., 8 and in C. novella, Barr. 9 Lastly, G. Bur- 

 meisteri, Barr., 10 differs from our English species in the opposite direction to C. 

 Barrandei, the glabella being smaller, the front area wider, and the surface of the 

 head smoother. Moreover, all of the Bohemian species have the lateral processes 

 of the neck-lobe nearly straight, and are distinctly different in the general contour 

 of the head from our English form. 



G. Belloci, Barrois, 11 has a narrower head and much longer cheek-spines which 

 arch outwards. C. megalops, M'Coy, 12 of the British Silurian, is much more circular 

 in the outline of the head, and has a smaller glabella and much more pro- 

 minent eyes. 



1 1878, Kayser, ' Abhandl. des geol. Specialk. Preussen,' Band 2, pt. 4, p. 17, pi. i, fig. 12, and 

 pi. iii, figs. 16—18. 



2 1846, Barr,, 'Notice prelim.,' p. 77. 



3 1852, Barr., ' Syst. Sil. Bohem.,' vol. i, p. 486, pi. xviii, figs. 38—48, Et, F. and G. 

 * Ibid., p. 483, pi. xviii, figs. 35—37, Et. E. 



5 Ibid., p. 489, pi. xviii, figs. 49—51, Et. F. 



6 Ibid., p. 490, pi. xviii, figs. 54—56, Et. F. 



7 Ibid., p. 490, pi. xviii, figs. 52, 53, Et. Q-. 



8 Ibid., p. 492, pi. xviii, figs. 57, 58, Et. E. 9 Ibid., p. 491, pi. xviii, figs. 59, 60, Et. E. 



10 Ibid., p. 484, pi. xviii, figs. 61—71, Et. D. (colony) and E. 



11 1883, Barrois, ' Ann. Soc. g£ol. Nord,' vol. x,p. 155, pi. vi,fig. 2 ; and 1886, ibid., vol. xiii, p. 136, 

 pi. ii, fig. 3. 



12 1846, M'Coy, ' Syn. Sil. Foss. Ireland,' p. 54, pi. iv, fig. 5. 



