]\fa)iiJicstcr Ulcj/inhs, Vol. h. (191 1), No. II 



XVII. The Upper Liassic Reptilia. Part 3. Micmr/eid/^. 



niacroptcrits (Seeley) and the Limbs of Min-or/cidi/s 



homnlosj^ojidyhis (Owen). 



]^y D. M. S. Watson, M.Sc 



Reuii Ko'.'eud'er ij^/h. igro. Keceii'cd for ■puhliialion Jaiuiary 24/ Ji, rgii. 



The Sedgewick Museum at Cambridge only contains 

 one Upper Liassic Plesiosaur, the beautiful skeleton 

 which is the t3'pe of Seeley's Plcsiosaurns inacropteriis. 

 This specimen, which is wonderfully complete, has never 

 been figured, and is so obscured by a very intractable 

 matrix and black paint that little can be made of it. 



Seeley gives the number of vertebrae as c. 39, d. 24, 

 s. I, cau. 28 ; he includes all the pectorals as dorsals. It 

 is quite impossible to check these numbers with any 

 pretence at accuracy, but the\^ are not far from the truth, 

 and indicate a reptile of the proportions of Mia-oclcidns 

 I/oinalospondj'lus, which has c. 40, p. + d. 5 + 17, s. 3, 

 cau. 20 + . 



None of the vertebra; are fit for description, but in all 

 regions they appear to be of Microcleidus t}'pe. 



Of the pectoral girdle only the dorsal rami of the 

 scapulre can be seen ; they project on each side of the 

 pectoral region as narrow bones of oval section pointing 

 slightly outward and backward, they agree exactly with 

 the same parts of the scapula o^ ]\[icrocleidiis Jiomalospon- 

 dylus. Their position shews that the whole girdle is 

 present undisturbed, and that it is of the Microcleidus 

 type, at any rate so far as the scapula; go. 



May 2gi/i, jgii. 



