NO. 1155. OSTEOLOG Y OF THE FA MIL Y ZEID.E—STA RES. All 



posteriorly; post- temporal forming an integral part of the skull; 

 arrangement of elements of suspensoriuni not typical; post clavicle of 

 a single piece; two pairs of superior pharyngeals bearing teeth; basi- 

 branchials united; vertebrae compressed anteriorly and number 13 + 

 17 + hypuial = 31; ])Osterior surface of centrum convex; posterior and 

 anterior zygopophyses present; inferior zygopophyses absent; para- 

 pophyses ankylosed at distal ends; articulation of ribs inferior on ver- 

 tebra3 or parapophyses ; epipleurals absent. 



DESCRIPTION IN DETAIL.' 



THE SKULL. 



(Plate XXXIII, figs, 1-3.; 



Exoccipitals {eo) entirely surrounding foramen magnum, broadly 

 meeting above and below; articular facets not meeting. 



Supraoccipital (.so) exposing only a small surface above; crest very 

 small; posteriorly two knife-like ridges, continuous with similar ones 

 on exoccipitals, extend downward to articular facets; between them 

 supraoccipital reaches down over upper suture of exoccipitals to border 

 ot foramen magnum. 



Basioccipital {ho) alone forming condyle for centrum of atlas. 



Frontals (/>•) large and exceedingly thick; much pitted and irregu- 

 larly honeycombed, breaking up large sensory canals posteriorly. 



Ethmoid (e) blade like, thin, and high; its length slightly less than 

 that of frontals, or about one-third length of entire skull; much carti- 

 hvge between its anterior end and vomer. 



Prefrontals {pf) rather long; no olfaetory foramen; large space 

 between them and ethmoid for olfactory nerve, connection with vomer 

 through intervention of cartilage. 



Vomer {v) wide and Hat; at right angles with ethmoid; small patches 

 of teeth at outer anterior corners only. 



Paraspheuoid {paH) sending lateral processes upward to articulate 

 with prootic; posterior end forked, nearly reaching to condyle of 

 basioccipital. 



Parietals {p) broadly meeting in front of supraoccipital. 



Alisphenoids {als) long, bordering upper two-thirds of brain cav- 

 ity; upper ends nearly meeting. 



Basis cranii well developed and thick; myodome large, not opening 

 to exterior i)osteriorly. 



SHOULDER GILDLR. 



(Plate XXXVI, figs. 11, 12.) 



Post-temporal {pot) bent at an obtuse angle rather than forked; from 

 deep notch for articulation of supraclavicle its respective ends run 

 upward and inward, and downward and inward at about the same 



'Elements not mentioned are typical or sufficiently explained by the drawings. 



