386 PROCEEDIIfGS OF THE GEOLOGICAL SOCIETY. [Jline 23, 



tain seven, also circular, teeth in each ; the teeth of the marginal row 

 are slightly truncated on the outer edge. This specimen was also 

 found in the Kimmeridge Clay at Kimmeridge, and must probably 

 be referred to the species named by Agassiz S])hcerodus gigas. 



2. Note on a large Saurian Hfmeeits /rom the Kimmeridge Clay of 

 the Dorset Coast. By J. W. Htjlke, Esq., F.E.S., F.G.S. 



[Plate XVI.] 



For the opportunity of bringing before the Society this remarkable 

 bone I am indebted to the great courtesy of J. C. Mansel, Esq., who, 

 in reply to an inquiry addressed by me to him respecting the genus 

 Pliosaurus, most liberally transmitted to me for study a large num- 

 ber of specimens from his unrivalled collection of Saurian bones from 

 Eimmeridge, amongst which was the subject of this note. Mr. 

 Mansel writes to me that this bone was found last year " amongst 

 the layers of shale immediately above the band of cement-stone 

 which rises from E. to W. on the west side of Clavell's Tower, be- 

 tween Eimmeridge Bay and Clavell's Head ; " and he called my at- 

 tention to it as differing from the common Enaliosaurian limb-bones. 



Description, — This stupendous bone has transversely elongated 

 extremities and a subcylindrical shaft. It has been broken across 

 at about 7 inches from its proximal extremity, and again 1 foot from 

 its distal end. Owing to the loss of small portions by splintering 

 and abrasion, the surfaces of the distal fracture do not meet accu- 

 rately. A long slip, reaching from this fracture to the anterior * 

 angle of the proximal terminal surface and including a small piece 

 of this latter, has been broken off the anterior (outer) border of the 

 bone and is wanting, as are also both the terminal epiphyses f. The 

 terminal surfaces are mammillated and rugous, and scarcely at all 

 abraded. The surface of the shaft is smooth and polished, composed 

 of a very dense cortex which in this situation is about '5 inch 

 thick, but which grows thinner towards the extremities, where also 

 its texture is less compact and its surface is rougher and coarsely 

 striated. There is no medullary canal. All the fractured surfaces 

 distinctly show the interior to consist of cancellous tissue. 



Proximal extremity. — This is much flatter than the distal. The 

 transversely lengthened convex terminal surface measures 11 inches 

 along the curve. Originally its length was somewhat greater ; for a 

 small piece of its front (outer) end is wanting. Its posterior end, 



* The terms anterior, posterior, upper, and under indicate the directions of 

 the borders and surfaces when the axis of the bone is supposed to lie in a 

 nearly horizontal plane, and nearly perpendicular to the axis of the trunk. 



t The term " epiphysis " is used here in a modified sense. "Dans les cro- 

 codiles et les tortues, les extrerait6s des os et leurs principales eminences sont 

 enduites de cartilages plus ou moins epais, qui durcissent et s'ossifient avec 

 I'age, mais dans lesquels il ne se forme point, comme dans les mammiferes, de 

 noyau osseux, separe pendant quelque temps du corps de I'os ou dela diaphyse 

 par uiae suture ; circonstance d'autant plus singuliere, que les eauriens, speciale- 

 ment les monitors, ont a leurs os longs des epiphyses tres-marquees." — Cuyiee, 

 Ossemens de Reptiles^ 1824, viii. p. 8. 



