ON PKOTEEOSAURUS SPENERI. 235 



The transverse processes are not well preserved ; but distinct 

 traces of them are observed in most of the vertebrae, and on one 

 or two the form is pretty well seen. They are simple, short, 

 and obtuse, and are lengthened a little in the direction of the 

 long axis of the centrum. 



The caudal vertebra? are longer in proportion to their height 

 than those of the trunk ; and the neural arch, as in them, is 

 completely united to the body, no suture or other trace of the 

 junction of the parts being perceptible. The spinous process is 

 as long proportionately, and those near the root of the tail are 

 of the same shape as those of the trunk. But further down they 

 become considerably contracted at the base in the direction of 

 the long axis, and gradually widen in the same place upwards. 

 The spine of the last joint on the slab, being the fifteenth or six- 

 teenth of the tail, exhibits at the upper margin an indication of 

 the peculiar bifurcation of the lower distal caudal spines of this 

 saurian. 



The anterior zygapophyses are considerably longer than those 

 of the trunk-vertebrae, and are more inclined upwards. Imme- 

 diately beneath the neural arch on either side of the centrum 

 there is a longitudinal ridge, which, near the centre of the body, 

 is produced a little into a short projecting tubercle, the trans- 

 verse process. The chevron bones forming the haemal arch are 

 about as long as the dorsal spine, but are much narrower, and 

 are of a spatulate form, being narrow at the proximal and flat 

 and small towards the outer extremity. They are not fixed, like 

 the processes, in connexion with the neural arch, but are articu- 

 lated below to the broad reflected margin of the posterior extre- 

 mity of the body, articulated, as it were, between the joints, and 

 are inclined backwards. Only a few of them remain, but two or 

 three are well displayed on a fragment of the counter-slab, which 

 has fortunately been preserved. 



The lumbar vertebrae are not well marked, and in this region 

 the specimen is unluckily fractured. Certainly two, perhaps 

 three, of the last vertebrae of the trunk are, however, apparently 

 anchylosed. Von Meyer seems to have been uncertain whether 



