562 Notices of Memoirs — Prof. H. O. Seeley. — On Beptilia. 



that the sujoposed sutures are fractures, and that the supposed inter- 

 clavicle has no existence, except as an ossification posterior to the 

 reputed clavicles. Then it M^as urged that these bones are un- 

 ])aralle]ed by any vertebrate clavicles, w^hile the reputed pubes of 

 Crocodiles and pre-pubes of other animals offer a more probable 

 analogy. 



The ossification in front of the pubis in Ornithosnurus is of similar 

 form in several genera. And in Crocodiles the ossification of the 

 fibrous extension which connects the reputed pubes w^ith the sternal 

 ribs would produce a bone like the supposed interclavicle of 

 Tguanodon. Hence it was urged that these bones in Iguanodon are 

 pre-pelvic, and the author identified them with the pre-pubic bones. 



HI. — The Classification of the Dinosaukia. By Professor H. 

 G. Seeley, F.E.S.^ 



THE author discussed the structure of the animals named Dinosaiiri a, 

 and concluded that the group had no existence, the constituent 

 animals belonging to two orders which have no affinity ; they are 

 named Omosauria and Cetiosauria, the former with a sub-avian pubis 

 and ischium ; the latter with those bones sub-lacertilian. 



The Omosauria is defined as having the ventral border of the 

 pubic bone notched out so that one limb is directed backward parallel 

 to the ischium, while the other limb is directed forward. The ilium 

 has a slender prolongation in front of the acetabulum. 



The Cetiosauria is defined by having the pubes directed forward 

 with a median symphysis, but with no posterior limb to the bone. 

 The anterior prolongation of the ilium has a vertical expansion. 



IV. — On the Mode of Development of the Young in Plesiosaurus. 

 By Professor H. G. Seeley, F.E.S.i 



THIS paper was descriptive of a specimen submitted to the author 

 by J. F. Walker, Esq., F.G.S. It is a phosphatized nodule 

 from the Lias of Whitby, measuring about 10 cm. by 7, by 5.' On 

 its surface are four more or less complete specimens regarded as 

 foetal Flesiosauri, together with fragments of at least three others. 

 They are remarkable for having the flesh mineralized with phosphate 

 of lime, and still show many characters of the external form of the 

 body, but slightly distorted by decomposition. Only one individual 

 has the head preserved, its extreme length is about 14 mm. The nares 

 are terminal, like those of an emydian chelonian. The superior aspect 

 of the head behind the frontal bone is occupied by muscular substance. 

 The skull rests on one side against the matrix, so that its transverse 

 width is not clearly shown, but it was wider than the neck, and 

 narrows in front of the orbit towards the nares, Avhich curve a little 

 downward. The eyes look obliquely upward and outward, and have 

 a diameter of two millimetres. The neck has a length of 4-5 centim. 

 Behind the head it is about 4 millim. deep, and as wide; it widens 

 to a centim. where the expansion takes place at the shoulders, and 

 there the depth is about 8 mm. A sharp median ridge down 

 ^ Abstracts of papers read before the British Association, Manchester, Sept. 1887. 



