ICHTHYOSArRID-E. 35 



41776 c. The centrum of an early posterior dorsal vertebra ; from 

 the Kimeridge Clay of the Isle of Portland, Dorsetshire. 

 The vertical diameter is 0,095 (3*75 inches), the transverse 

 0,111 (4-35 inches), and the length 0,031 (1-2 inch) ; 

 the costal facets have united into a single one placed 

 rather below the median horizontal line. In contour this 

 specimen closely resembles the rather larger posterior 

 dorsal figured by Phillips in his ' Geology of Oxford,' 

 p. 338, diagram 130, figs. 3, 4, but in that specimen the 

 costal facets are distinct. The contour of this specimen 

 bears the same relation to the next as presented by the 

 centrum of I. trigonus, No. R. 9 (p. 25) to No. 24684 d 

 (p. 26). Purchased, 1869. 



47428. The centrum of a late posterior dorsal vertebra ; from the 

 Oxford Clay of Whittlesea, near Peterborough. Vertical 

 diameter 0,100 (3*9 inches), transverse diameter 0,106 

 (4*15 inches), length 0,025 (1*3 inch). The costal facets 

 are double, and the contour of the terminal faces is similar 

 to that of the corresponding vertebra of i". trigonus, 

 No. 24684 d (p. 26). 



Sharp Collection. Purchased, 1876. 



47428 a. The centrum of an anterior caudal vertebra, associated 

 with the preceding. Although somewhat larger (which 

 may be due to pressure) this specimen closely accords with 

 the caudal figured by Phillips in his ' Geology of Oxford/ 

 p. 338. Sharp Collection. 



41776 d. The centrum of a smaller caudal vertebra ; from the 

 Kimeridge Clay of Weymouth, Dorsetshire. 



Purchased, 1869. 



46794 b. The centrum of a caudal vertebra ; from near Devizes. 

 The centre is perforated. Cunnington Collection. 



Specifically undetermined specimens from the Kimeridge and Oxford 

 Clays belonging either to Ichthyosaurus or OphthalniQsaurus. 



41881, 42371, 43290. Five imperfect teeth, of a more slender type 

 than those referred to /. trigonus and 1. dilatatus; from 

 the Kimeridge Clay of Weymouth, Dorsetshire. 



Purchased. 

 d2 



