160 SAUKOPTERYGIA. 



Group A. — The arches of the cervical vertebrae (fig. 56) very tall 

 and short antero-posteriorly, with the longer axis of the zygapo- 

 physes directed transversely, and the pre- and postzygapo- 

 physes either in contact or separated by a very short and deep 

 notch; posterior border of neural spine above intervertebral 

 space. 



Serial position uncertain. 



Thaumatosaurus indicus, Lydekker \ 

 Syn. Plesiosaurus indicus, Lydekker 2 . 



Known only by the mandibular symphysis, which, allowing for 

 the effects of pressure in the latter, cannot be specifically distin- 

 guished from the type mandible of T. arcuatus, although the difference 

 in the geological horizon of the two forms probably indicates specific 

 distinction. 



Whether this and the following species belong to the first or 

 second group cannot be determined until the arches of the cervical 

 vertebrae are known. 



Hob. India. 



R. 1401. Cast of the mandibular symphysis. The original, which is 

 the type, and is preserved in the Indian Museum, Cal- 

 cutta, was obtained from the Umia stage (Upper Jurassic) 

 of the Upper Gondwanas of Kach. It is described by the 

 writer in the ' Rec. Geol. Surv. Ind.' vol. x. p. 41, and 

 described and figured in the ' Palaeontologia Indica ' 

 (Mem. Geol. Surv. Ind.), ser. iv. vol. i. pt. iii. p. 28, pi. vi. 

 fig. 1, as Plesiosaurus. It was referred to the present genus 

 in the ' Eec. Geol. Surv. Ind.' vol. xxii. p. 50, where a 

 restored figure is given which is reproduced in woodcut fig. 

 47, B (p. 150). There is a diamond-shaped protuberance at 

 the posterior extremity of the oral surface of the symphysis 

 similar to one existing in T. arcuatus No. 2030*, although 

 the latter has been longitudinally split by pressure. 



Made in the Museum, 1888. 



Thaumatosaurus oolithicus, Meyer 3 . 



Syn. Liopleurodon bucJdandi, Sauvage 4 . 



The type species. Imperfectly known, but probably attaining 



1 Eec. Geol. Surv. Ind. vol. x. p. 41 (1877). — Plesiosaurus. 2 Loo. cit. 



3 Neues Jahrb. 1841, p. 176. 



* Bull. Soc. Geol. France, ser. 3, vol. i. p. 378 (1873). 



