698 EEPORT— 1887. 



rapidly downward in nvery specimen. The lieifrlit of tbe body was not more than 

 halt' its width. The limbs are imperfectly preserved. The distance between them 

 on the left side is 2-4 centimetres. The anterior limb appears to be the larger. 

 The entire length of the specimen is 12-5 centimetres. 



This individual lies over the neclc of another specimen which was larger, and 

 appears to have measured fifteen centimetres without the head. It shows the fore 

 limbs to have been very wide relatively to their length. The limb measured in 

 tbe antero-posterior direction 1-1 centimetre at the junction with the shoulder on 

 the right side ; it is flattened, extended horizontally, imperfect distall^', and curved 

 somewhat backward, but evidently short as compared with the adult. The hind 

 limbs of this specimen are not seen. 



Other individuals are smaller, and have the body only about half as wide. 

 They are very narrow in the anterior part of the body, and t'lere appears to be 

 only a slight budding of the fore limbs. 



Hence the author regarded this specimen as showing that Plesiosaur us was vivi- 

 parous, and that in one species Iroai the Lias many were produced at one birth. The 

 species was probably a long-necked one, and may have been P. honiolospondylus, 

 since the bead in youug animals is relatively large, and here it is J the total length 

 of the animal. 



6, On the reputed Clavicles and Iv.terr.lavlcles of Tguanodon. 

 Bi/ Professor H. G. Seei.ey, F.B.S. 



The author showed by superimposing a figure of the reputed clavicle upon the 

 bone figured by Mr. Iluike as clavicle and interclavicle of Iguanodon (' Quart. 

 Jour. Geol. Soc' vol. xli. ])1. xiv.), that the supposed sutures are fractures, and 

 that the supposed intercla\icle lias no existence, except as an ossilication posterior 

 to the reputed clavicles. Then it was urged that these bones are unparalleled by 

 any vertebrate clavicles, while the reputed pubes of crocodiles and pre-pubes of 

 other animals offer a more probable analogy. The ossification in front of the pubis 

 in Oruithosaurs is of similar form in several genera; and in ciocodiles the e)ssi£i- 

 cation of the fibrous extension which connects the reputed pubes with the sternal 

 ribs would produce a bone like the supposed interclavicle of Iguanodon. Hence it 

 was urged that these bones in Iguanodon are pre-pelvic, and the author identified 

 them with the pre-pubic bones. 



7. On Cnmnoria, an. IijuaHodout Oenus foniuled upon the Iguanodon 

 Prestwichi, Hulke. Lij Profes.sor H. G. Seeley, F.B.S. 



This genus is named from Cumnor, the locality where the fossil was found. It 

 is separated from Iguanodon by many characters, such as the different type of 

 parallel ridging and coarser serration of the teetli. The vertebrffi are relatively 

 wider, the neural arch and centrum both being more depressed ; the laminpe of the 

 neural arch are very stout, and the neural canal very small; the sacral vertebrre are 

 not anchylosed, are only four in number, .and are convex on the ventral .surface. 

 The early caudal vertebras are reduced in length, and have tbe neural arch small. 

 The astragalus and calcaneum are separate. In these and 'other characters this 

 Kimmeridge clay type differs from Iguanodon, and in some of them approximates 

 towards Hypsilophodon and Mochlodon. 



8, The Classification of the Dinosanria. By Professor H. G. Seeley, F.B.S. 



The author discussed the structure of tbe animals named Dinosanria, and con- 

 cluded that the group had no existence, the constituent animals belon^nng to two 

 orders, which have no near affinity : one with a sub-avian pubis and ischium, the 

 other with those bones sub-lacertilian. 



The Oknithischi.i ' is defined as having the ventral border of tbe pubic bone 



' These "■roups are more fully defined in a communication to the Hojal Society, 

 read November 23, 1887. 



