186 SATJKOPTERYGIA. 



Reptilia,' pt. i. pi. xvii., 1851) is from the Chalk of Sussex ; the 

 specimens from the Cambridge Greensand have been separated by 

 Seeley as Plesiosaurus ichthyospondylus, without any specific cha- 

 racters being given. The Russian specimens are from the " Osteolite," 

 which is probably the equivalent of the Gault. It appears not 

 improbable that the later cervical and " pectoral " vertebra? figured 

 in the ' Cretaceous Reptilia,' pt. i. pi. xx. as Plesiosaurus pachyomus 

 (which was founded upon an unfigured propodial) are referable to 

 this species. Plesiosaurus balticus from the Chalk of Prussia was 

 founded upon "pectoral" vertebra? and a propodial, the latter 

 being of the type of 0. trochanter his. 



Hob. Europe (England, Russia \ and Germany 2 ). 



The following specimens are from the Cambridge Greensand. It is 

 probable that the greater number of the cervicals belong to a 

 single individual, which ivas immature. 



35295. The centrum of an anterior cervical vertebra. Figured by 

 {Fig.) Owen in his ' Cretaceous Reptilia ' (Mon. Pal. Soc), suppl. 

 iv. pi. iv. figs. 1-4 (1864). Length 0,031 (1-22 inches), 

 height 0,035 (1-36 inches), width 0,036 (1-42 inches). 



Purchased, 1859. 



35295 a. The crushed centrum of an anterior cervical vertebra. 

 {Fig.) Figured, op. cit. pi. iv. figs. 5, 6. Purchased, 1859. 



35295 b. The centrum and left side of the neural arch of a larger 



{Fig.) and probably later cervical vertebra. Figured, op. cit. 



pi. iv. fig. 9. Purchased, 1859. 



35295 c. The centrum of a somewhat crushed cervical vertebra. 

 {Fig.) Figured, op. cit. pi. iv. figs. 7, 8, and pi. v. fig. 7. 



Purchased, 1859. 



35295 d. A cervical vertebra, wanting the ribs, zygapophyses, and 



{Fig.) neural spine. Figured, op. cit. pi. iv. fig. 10, and pi. v. 



fig. 1. Purchased, 1859. 



35295 e. A very similar specimen showing the zygapophyses of the 

 {Fig.) left side. Figured, op. cit. pi. iv. fig. 11, and pi. v. figs. 2 

 and 6. The slight curvature of the zygapophysial articu- 

 lations characteristic of the group is well shown. 



Purchased, 1859. 



Kiprijanoff, Mem. Ac. Imp. St. Petersbourg, vol. xxx. art. 6, p. 5. 

 Schroder, Jahrb. preuss. geol. Landesanstalt for 1884, pp. 297, 315. 



