82 BRITISH FOSSIL REPTILES. 



Institution, Birmingham, the length of the coracoid is 4 inches 5 lines, and the breadth 

 3 inches ; the length of the humerus of the same specimen is 3 inches 10 lines, the 

 breadth of its distal end is 3 inches. The transverse diameter of the radius equals the 

 antero-posterior diameter of the centrums of two of the parallel vertebrae ; its anterior 

 margin is notched. The ulna has a corresponding size, with a smaller anterior notch 

 circumscribing with an apposed notch in the radius a roundish vacuity. These bones 

 were anchylosed together and to the humerus in the Birmingham specimen. The 

 ' manus ' commences by three transversely oval carpals, of which the radial one is 

 notched, as in the radius ; but this character is not repeated, as in Ich. acutirostris and 

 Ich. platyodon, in the next distal bone, nor is the radial digit bifurcate, as in Ich. com- 

 munis and Ich. intermedius. There are but three series of digital bones, with a fourth 

 shorter marginal series of smaller ossicles. 



In the hind paddle (Tab. XXVIII, fig. 6) the femur, like the humerus, has a longer 

 shaft than usual, and not so proportionally broad a distal end. The tibia is notched 

 anteriorly like the radius, but not so deeply ; the corresponding tarsal bone is more 

 feebly emarginate. In this fin, also, there are but three series of digital ossicles. 



In the Museum of the British Institution there is a skeleton of Ich. fenuirostris, 

 tliirteen feet in length : it is from the Lias of Lyme Regis, Dorsetshire. Evidences of 

 the same species have also been obtained from the Lias of Stratford-on-Avon, of Bristol, 

 of Street, Somersetshire, and at Barrow-on-Soar, Leicestershire. 



/;. Ichthyosaurus longirostris, Ow. Tab. XXI, fig. 2; Tab. XXIV, fig. 3; Tab. 



XXVIII, figs. 7, 8, 9. 



The specimens in the British Museum, from the Lias of Barrow-on-Soar, on which 

 the present species is founded, and the least incomplete of which is the subject of figure 7, 

 Tab. XXVIII, have borne the above specific name in the Public Gallery of the Depart- 

 ment of Geology for fifteen years. The description was reserved for the present Work, 

 and I regret the unavoidable circumstances which have delayed its publication. 



Reckoning the lost terminal caudal vertebrae according to the guiding analogies I 

 estimate the total length of the animal to include four lengths of the skull. Of this part 

 the length of the rostral extension anterior to the orbit is four and a quarter times the 

 antero-posterior diameter of that cavity : and yet the orbit is relatively larger than in 

 Ichthyosaurus fenuirostris. 



The teeth correspond in size with the slenderness of their supporting jaws ; they are 

 of difficult detection ; the best preserved show crowns, as in fig. 9, Tab. XXVIII. With 

 sufficient magnifying power traces of longitudinal striae are discernible on the enamelled 

 crown ; the cemented base is as little tumid as in Ich. tenuirostris. In the relative 



