288 PALEONTOLOGY. 



Orodus variabilis, Ctenacanthusfurcicarinahis, C. ixirviilas^ Lisiracanthus 

 Hildrethi, Orfhacanthus gracilis, Flatyodm^ lineatus, Ctenodus serratus, 

 C. retiridatus, Dipterus Shenroodi, and Heliodas Lesleyi. The new 

 genus Flatyodus is founded for the reception of an Elasmobranch allied 

 to Deltodus, and the genus Heliodus for a Ganoid related to Dipterus, 



H. A. N. 



Owen, Prof. Richard. On Possil Evidences of a Sirenian Mammal 



(Eotheriurn cegyptiacum-, Owen) from the Nummulitic Eocene of 



the Mokattam Cliffs, near Cairo. Quart. Journ. Geol. Soc. vol. 



xxxi. pp. 100-105, pi. iii. 



A cast of the brain with parts of the occipital and sphenoidal regions 



of the skull. The new Sirenian is regarded as nearly allied to Felsi- 



notherium, Halitherium, and Metaxitherium. The brain, as compared 



with Manatus, is deficient in breadth and depth. L. C. M. 



. Monograph on the British Fossil Eeptilia of the Mesozoic 



formations. — Part II. Pp. 15-93, plates iii. xxii. Pal. Soc. 



1. On Bothriospondylus : this genus is founded upon vertebrse charac- 

 terized by " long, low, and deep cavity, overarched by that part of the 

 side of the centrum supporting the neurapophyses," very greatly redu- 

 cing the width at that spot; large unossitied spaces or cancelli in centrum ; 

 articular ends of trunk-vertebrae feebly convex and concave respec- 

 tively : the neural spine was anchylosed, but has been broken away in all 

 cases. The species described are : — B. suffossus : a greatly depressed 

 sacral vertebral centrum, a terminal centrum of sacral vertebra are 

 figured and described, also 4 dorso-lumbar vertebrae in which parapo- 

 physes are absent and the centrum is only subcompressed. Kim. Clay, 

 Swindon. — B. rohnstus : a centrum of dorso-lumbar vertebra from the 

 Porest Marble of Bradford (Wilts) is described. It is suggested that 

 the teeth Cordiodon of the author's ' Odontography ' from the same 

 locality may possibly belong to this species. — B. elongatus : an incom- 

 plete centrum over 8 inches long is referred to this genus, since it has 

 the long and deep lateral cavity and large cancelli. Weald. — B. magnus : 

 an anterior dorsal centrum of short form, the terminal facet 8 inches 

 in vertical diameter : very large cancelli. Weald, Isle of Wight. 



2. On Cetiosaurus : one vertebra is drawn natural size, and the long 

 bones (illustrated by 10 woodcuts) of G. longus, from Gt. Oolite of 

 Kirtlington. The length of the trunk and tail, exclusive of the head, is 

 estimated at 31 to 36 feet. 



3. On Omosaurus. In Kimmeridge Clay, Swindon, were found parts 

 of the vertebral column, pelvis, femur, tibia, and almost all the bones of 

 the left fore limb of 0. armatus, Ow. The middle dorsal vertebra is 

 feebly convexo-concave, the neurapophyses coalesced, the rib-head fitted 

 into a cavity on the neural spine without a parapophysis ; neural canal 

 large ; neural arch strengthened by several ridges. Last lumbar seems 

 confluent with first sacral. 5 sacral in apposition, with pleurapophyses 

 attached ; in the same block were 8 hinder trunk- vertebrae dislocated, 

 and 4 caudals also displaced. Anterior caudals united by a syndesmosal 



