24 ORDOVICTAN AND SILURIAN BBLLEROPHONTACEA. 



conform close]y to the above definition. The entire and scarcely sinuated 

 mouth seems a character of primary importance. 



1. Cyrtolites budleighensis, sp nov. Plate IV, figs. 12 — 14. 



Specific Characters. — Shell high, somewhat compressed, composed of 2 — 3 

 whorls rather higher than wide, in contact with but not overlapping each other, 

 the last whorl rapidly increasing in size. Umbilicus large, open, shallow, 

 completely exposing all the whorls, with centre situated below centre of shell. 

 Whorls broadly lanceolate to subrhomboidal in cross-section, widest at about 

 one-third their height; dorsum narrow, subangular, becoming somewhat rounded 

 near mouth ; sides convex, swelling out to maximum diameter below middle, then 

 forming obtuse subangular umbilical edges and sloping inwards to umbilicus. 

 Mouth vertical, rhomboidal in shape, subangular above and widest at umbilical 

 edges; lateral margins obtusely angulated and projecting forwards, with upper 

 edges inclined to dorsum at about 60°. Surface of whorls with faint traces of 

 transverse lines and growth ridges ; and with some weak transverse broad ribs or 

 swellings on upper part near mouth. 



Dimensions. — 



Height of shell ....... 28*0 mm. 



Height of outer whorl near mouth , . . 17'0 ,, 



Width of outer whorl near mouth . . . UOO „ 



Horizon. — Ordovician pebbles in Triassic conglomerate. 



Locality. — Budleigh Salterton. 



Remarks. — Towards the mouth the dorsum almost loses its carination. The 

 specimens [G. 15296, 15298, 15299, 15301], all of which are in the British 

 Museum, are in the state of internal casts and so do not show the external 

 ornament, and the transverse ribs or swellings in any part are somewhat indistinct. 

 The cross-section and enrolment of the shell resemble G. suhplanns, Ulrich^ and 

 C. retrorsus, Ulrich yar. fill morensis," from the Ordovician of Minnesota. 



2. Cyrtolites craigensis, sp. nov. Plate IV, fig. 15. 



Specific Characters. — Shell of 3 — 4 whorls in contact, but not overlapping, 

 rapidly increasing in size, but more rapidly in height than width, subtriangular to 

 subrhomboidal in section, dorsally carinate, and sharply angular ; sides of whorls 

 convex ; umbilical edge subangular ; umbilical slope steep or almost vertical. 

 Umbilicus wide, deep, open, exposing all inner wdiorls; centre of umbilicus 

 situated at rather more than one-third the height of shell. Mouth not expanded, 

 higher than wide, oblique, sloping backwards ; lateral edges arched gently 

 forwards. Surface unknown (smooth?). 



1 Ulrich and Scofield, op. cit., p. 862, pi. Ixii, figs. 40-44. " Ibid., p. 861, pi. Ixii, figs. 38, 39. 



