Dr. C. W. Andrews—The Skeleton of Peloneustes. 111 
Oxford Clay Reptiles, including the beautifully preserved and nearly 
complete examples of Cryptocleidus oxoniensis and the remains of 
Cetiosaurus leedsi, now mounted in the Gallery of Fossil Reptiles. 
So far as I am aware, this is the first skeleton of a Pliosaur that has 
been mounted so as to show the true form of the body in those reptiles. 
All the bones belong to a single individual, but the left-hand paddle 
and the distal portion of the other paddles being wanting, they have 
been represented by plaster models made from the paddles of another 
individual, which are exhibited on the floor of the case. The left 
ischium has been modelled from that of the opposite side. 
Peloneustes philarchus was first noticed by the late Professor H. G. 
Seeley’ under the name Plesiosaurus philarchus. Subsequently 
Mr. Lydekker? gave a more complete account of the species and 
referred it to a new genus, Peloneustes. The structure of the skull 
was described by the present writer in the Ann. Mag. Nat. Hist., 
1895, ser. vi, vol. xvi, p. 242. é 
Peloneustes, though considerably smaller than the other Pliosaurs, 
exhibits all the characters peculiar to that family, viz. relatively large 
head, short neck with double-headed cervical ribs, absence of a median 
symphysis of the scapule, greatly elongated ischia, and hind paddles 
larger than the fore. Mr. Lydekker, however, considers that in some 
respects it is more primitive than the larger forms, and tends to 
bridge the gap between them and the true Plesiosaurs. 
The skull, which in the present specimen is somewhat crushed and 
distorted, is relatively large and the snout is considerably elongated, 
the length of head being about two and a half times its width at the 
posterior end. There are six tecth in the premaxilla, and twenty- 
eight to thirty in the maxilla; in the lower jaw there are about 
thirty-five teeth on each side, of which fifteen to sixteen are in the 
symphyseal region. The teeth themselves are slender and sharp- 
pointed; they are circular in section, and the enamel-covered crown 
bears numerous fine longitudinal ridges, some of which extend to the 
apex. The neck is short, and is composed of twenty-one or twenty- 
two vertebree, including the atlas and axis; the centra are short and 
slightly biconcave, the neural arches and spines are high. All the 
cervicals behind the united atlas and axis, with the exception of the 
last, bear double-headed ribs, but the facets for the upper and lower 
heads are separated by a slight ridge only; the last cervical seems to 
have had only one head, and the same is the case with the pectorals 
and dorsals. Of these there seem to have been two or three of the 
former and twenty-two or twenty-three of the latter, all bearing 
comparatively slender ribs. The number of sacral-and caudal vertebree 
is not definitely known. 
The shoulder-girdle is typically Pliosaurian, the coracoids are large 
thin sheets of bone; the scapule are triradiate, but the ventral rami 
do not meet one another in the mid-ventral line, nor do they meet the 
coracoid. Some specimens show that a triangular interclavicle was 
interposed between the ventral ends of the scapule. The fore paddle 
1 Index to Aves, etc., in the Cambridge Museum, 1869, p. 139. 
* Quart. Journ. Geol. Soc., 1889, vol, xlv,. p. 48. 
