Dr. C. W. Andrews—An Ichthyosaur from Peterborough. 207 
with the outer end of the clavicles. These are strongly curved bones, 
terminating externaliy in a point and uniting with one another in the 
middle line by an irregularly interdigitating suture, which may have 
been obliterated in advanced life. The upper surface of the middle 
portion of the clayicular arch is deeply channelled for the reception of 
the anterior bar of the T-shaped interclavicle, the posterior process of 
which extends back beneath the coracoid symphysis. 
» The fore-limb (Fig. 3, p. 205) is much larger than the hind, and forms 
a wide and powerful paddle. The humerus (/.) is a short and very 
Fic. 5.—Ophthalmosawrus icenicus, Seeley. Left hind-limb. A, dorsal surface of 
paddle ; B, ventral surface of femur ; C, proximal end of femur; D, distal end 
of femur. About + nat. size. 
a.b. anterior border of proximal end of femur; a.s. anterior surface of femur ; 
d.r. dorsal ridge of temur; f. fibula; ff. facet for fibula; id. fibulare ; 
int. intermedium ; 7.5. lower border of proximal end of femur; p.d. posterior 
border of ditto; ¢. tibia; ¢.f. facet for tibia; ¢is. tibiale; 1m, the three 
digits. In figure C the line ab marks the direction of the long axis of the 
distal end of the bone in relation to the proximal end. } 
stout bone, the distal end of which is expanded, and articulates with 
the radius (7.), ulna (w.), and to a varying degree with a postaxial 
element, usually regarded as the pisiform (p.). ‘he proximal row of 
carpals consists of the radiale (rad.), the intermedium (7nt.), and the 
ulnare (w/n.). ‘There are five digits (1-v), the postaxial one borne by 
the pisiform being much reduced, The paddle bones do not form 
a close. mosaic as in most Ichthyosaurs, but seem to have been 
separated by a considerable amount of cartilage throughout life. 
