W. H. Mudleston — On the YorJcshire Oolites. 107 



digits in manus and pes ; second row of carpal and tarsal bones 

 nnossified. Sternal bones parial/ Pnbes projecting in front, and 

 united distally by cartilage ; no post-pubis. 



(1.) Family Atlantosanridce. A pituitary canal. Ischia directed 



downward, with expanded extremities meeting on median line. 



Sacrum bollow. Anterior caudals with lateral cavities. 



(2.) Family Biplodocidm. Dentition weak. Brain inclined backward. 



Large pituitary fossa. Two antorbital openings. Ischia with 



straight shaft, not expanded distally, directed downward and 



backward, with ends meeting on median line. Caudals deeply 



excavated below. Chevrons with both anterior and posterior 



branches. 



(3.) Family Morosauridce. Small pituitary fossa. Ischia slender, 



with twisted shaft, directed backward, and sides meeting on 



median line. Anterior caudals solid. 



The Sauropoda are the order of Dinosaurs having the nearest 



affinities with the Crocodilia, especially through some of the extinct 



forms. DiplodocuSj for example, resembles Belodon of the Triassic, 



particularly in the large antorbital vacuities of the skull, the posterior 



position of the external nasal aperture, as well as in other features. 



The genus Aetosaurus, from the same formation, is an intermediate 



form, and represents a distinct order, which may be called Aetomuria. 



The nearer relations of these groups will be discussed by the writer 



elsewhere. 



Tale College, New Haven, Jan. 21, 1884. 



III. — Contributions to the Paleontology of the Yorkshire 



Oolites. 



Ey "Wilfrid H. Htjdleston, M.A., F.G.S. 



(Continued from Dec. III. Vol. I. p. 63.) 



(PLATE IV.) 



30. — Cehithium (?) CANiNUBi, sp. D. PI. IV, Figs. 1, la, 2. 



Description. — Specimen from the Dogger (zone 1), Peak (Blue 

 Wyke). Bean Collection, British Museum. Figs. 1 and la. 



Length (restored) 51 millimetres. 



Width 21 ,, 



Eatio of body-whorl to entire shell 37 : 100. 



Spiral angle 32°. 



Shell conical, moderately long, with perhaps a rudimentary um- 

 bilicus. The complete spire would consist of about 10 whorls, 

 ■which increase under a regular angle. The surface of the apical 

 whorls in this specimen is not well preserved, but the five anterior 

 whorls are in good condition ; they are smooth, somewhat tumid 

 towards the centre, and separated by a suture of moderate depth. 

 Wavy longitudinal lines, apparently lines of growth, are observed, 

 but there is no trace of any other ornament. Base of body- whorl 



^ Ceteosaurus has been figured with a single sternal bone by Phillips and other 

 authorities. The writer recently examined the original specimen at Oxford, and 

 found portions of two of these bones, which strongly resemble the sternal plates of 

 American Sauropoda. 



