the Cretaceous and Tertiary Formations. 449 



nisliiiig the largest, and tbe last the smallest portion of the ar- 

 ticular surface. The body of the ilium is remarkably slender, 

 and the proximal end was probably attached to a vertebra merely 

 bv cartilage. The distal extremity is much expanded, sub- 

 rhombic in outline, and has three nearly equal facets on its ar- 

 ticuLir surface, that forming part of the acetabulum being the 

 The adjoining proximal end of the pubis is inoio com- 

 ' *]ian that of the ilium, and has three eorrosju.iKiing ar- 

 ::K-ets, the acetabular being nearly Hat. and the fillers 

 . The portion below is flattened, and lias a loramen 

 -; anterior margin. The proximal end of the ischium is 

 :i!-'' trihedral, and somewhat smaller than that of the pubis. 

 The articular surfaces of all these bones were thickly capped 

 with cartilage. The few phalanges found with these remains 

 are rod-like, depressed, and much constricted medially. The 

 ends ai-e transverse, and have been covered with cartilage. 

 Thev indicate that the limbs were paddles, not unlike those of 

 Plmosrmnis, but more slender. 



Length of axis, 26- lines. 



hength of axis, with odontoid process, 32- " 



\\ idth between diapophyses, 26-8 " 



>> Kith of articular ball, , . 11-25" 



%'th of articular ball, 9-25" 



Length from edge of cup to end of ball in eleventh 



vertebra, .. 25- " 



^Vidth of ball, . . 14- " 



Depthofball, ."'"'"...!."]".]].[! 12- " 



Length of first caudal on inferior surface, 16- '' 



)> idth of articular cup, 14-5 " 



Depth of cup, .. ^' - . 15- " 



Length of quadrate, 30-75 " 



i '-ans verse extent of distaUnd, - 18-75 " 



l^ength of pterygoid bearing the five anterior teeth, 38-5 " 

 ^ength of portion with the five posterior teeth,.--. 23- " 

 Antero-posterior diameter of distal end of iUum,. - . 14-5 « 



1 ransverse diameter 1 1 30 " 



^'ameter of shaft, .['. V.'". 4-75 « 



^^reatest diameter of proximal end of pubis, 16-30 " 



iransverse diameter, 10- " 



l^reatest diameter of proximal end of ischium, ... - 1 4- " 



Iransverse diameter,.. 9' " 



bw^^^P®^^®^ is readily distinguished from Clidastes iguanavus, 

 rii; 1 ^^'f depressed and more constricted centrum in the ante- 

 C7 ^?^als. It differs essentially also from Clidast^s cineriarum 

 doS^° having transverse articular faces in the vertebrge of the 

 snp? lumbar regdon. The specimens representmg this 



Fwies were discovered, in November last, by Mr. H. B. Sargent 



