0. C. Marsh—Structure of Mosasauroid Reptiles. 455 
larger than Vertebree with rudimentary zygosphenal articu- 
tethers sari vertebrae with sitccianed eaten six. 
Chevrons articulated. 
Several species with the above generic characters have been 
referred to Liodon and to Holcodus by Prof. Cope. From the 
former they are widely separated by the teeth, which in Liodon 
anceps Owen, the type species, are compressed, and smooth, as 
the name implies. The Holcodus of Gibbes was based on teeth 
of Hyposaurus, and a single dental crown, which indeed some- 
what resembles the teeth of Lestosawrus in surface characte 
Widely separated, also, from Mosasaurus, Platecarpus, Clidastes, 
and destosaurus, by the articular chevrons, as well as by other 
Lestosaurus simus, sp. Nov. 
This species is established on the complete anterior portion 
of a skeleton, including skull, paddles and vertebra, of one 
individual, and portions of several others which fully supple- 
Temoved from the rock, and every bone numbered, eo 
