CERATIOCARIS SOLENOIDES. 53 



The carapace is elongate, boat-shaped, straight above, curved below, rounded 

 to a blunt point (on the medial line) in front; truncated obliquely from above 

 downwards and backwards behind, making with the postero-ventral upward curve 

 a blunt point below the medial line. 



PL VIII, figs. 4 a, 4 6. Cambridge Museum 6/40, marked " Ceratiocaris 

 solenoides, M'Coy." In dark-grey, micaceous, fine-grained sandstone, slightly 

 calcareous ; from Benson Knot, Kendal, Westmoreland. This is an imperfect 

 carapace, embedded whilst open to some extent, and therefore extra wide in its 

 dorsal aspect. Prof. M'Coy's fig. 5 a is a sketch of this specimen free of matrix ; but 

 the broken end is not correctly given ; there is no eye-spot at all, and the figure is 

 reversed. 



PL VIII, fig. 5. Cambridge Museum, with 6/8. Benson Knot. In the same 

 sandstone as 6/40. The back and the left-hand (posterior) end in the figure are 

 obscured by matrix. 



PL VIII, figs. 7 a, 7 6. Cambridge Museum 6/41, marked " Ceratiocaris 

 solenoides, M'Coy." Benson Knot. In the same sandstone. 



This seems to be M'Coy's fig. 5 ; if so, the sketch is reversed, and there is no 

 eye-spot (only a little accidental hole near the anterior end). It has traces of 

 longitudinal strias, and of the ventral rim. 



PL VIII, figs. 8 a, 8b. Cambridge Museum 6/8. Benson Knot. In the same 

 sandstone. The left-hand end in the figure is obscured by matrix (anterior). 



Another, marked ' R. I. M., Benson Knot,' is the internal cast of a right valve, 

 partly buried at each end. There is some obscure lineation ; fine longitudinal 

 strias being visible (under the lens) on the anterior half. 



PL VIII, figs. 9 a, 9 b. Mus. Pract. Geol. x - x \- (Cat., 1878, p. 142). In 

 Upper- Ludlow dark-grey, micaceous, fine-grained sandstone ; from Benson Knot, 

 Kendal. A convex cast ; smooth ; with the ends partially obscured, especially 

 that at the left-hand of the figure. 



PL VIII, figs. 10 a, 10 b. Cambridge Museum, with 6/41. In dark-grey, 

 micaceous, fine-grained sandstone, slightly calcareous ; from Benson Knot. It 

 has very faint traces of longitudinal stria?, and a slight trace of the ventral rim. 

 There are two small adventitious pits on the anterior third of the valve, but no 

 ocular spot. 



