CHIONIS MINOR. 103 



Sternum measures 2.40 inches by 1.20 at upper borders, aud is there- 

 fore exactly twice as long as broad. (Others measure 2.5 by 1.3, No. 

 32 <? ; 2.42 by 1.20, No. 232.) The manubrial process projects slightly ia 

 front of anterior border, sending downward a small, thin beak-like 

 process. Articulating surface for coracoid extends from external and 

 posterior margin of manubrial process, nearly meeting its fellow above 

 it backward and outward, to an angular prominence on the ridges limiting 

 steruo-coracoid articulation .80 inch from the manubrial process. When 

 the coracoid has been removed, the anterior margin of sternum is nearly- 

 transverse, showing only a shallow curve upon each side. The eostafi 

 process projects laterally beyond lateral margins of sternum 0.22 ineli, 

 and behind coracoid articulation. There thus presents on each side a 

 triangular space, defined in front by the ridge limiting steruo-coracoict 

 articulation, its base occupied by a grooved facet for coracoid^ aud its 

 two other sides constituted by the horizontal and lateral margins, of tke 

 costal process. 



The ridge limiting steruo-coracoid articulation inferiorly is prominent 

 and sinuous — bow-shaped. Itextendsnearly to lateral margin of sternum, 

 which is a thickened ridge, bearing facets for the articulations of ribs 

 on its flattened wide edge, and passing upward to join costal process at 

 nearly a right angle. Costal process is flat and obtusely pyramidal in. 

 shape. It projects upward and outward, and covers the posterior as[)ect 

 of steruo-coracoid articulation. Body is slightly constricted at its middle 

 part, where it measures 1.00, expanding again posteriorly to measure 1.40 

 inches from apex to apex of its external lamiute. Posterior border is 

 convex, the xiphoid i:)rocess being cut off transv^ersely. The posterior 

 border is deeply incised on each side by two notches, of which the inner 

 measures .40 and the outer .45 in depth, measuring from the curved 

 margin indicated by the extremities of the intervening strips of bone 

 (hyposternal elements of Owen). The outer notch is thus a little deeper 

 than the inner, yet, owing to the convexity of the posterior borders of 

 the lateral parts of the sternum, the two lamina? limiting the notches 

 are almost exactly of equal length. The margins of the lateral sternal 

 elements are thickened, as already stated, becoming stoutest in the area 



that vertebra which bears a distinct, though small and asternal, rib. Removing this 

 disputed one from his cervical series, and adding it to the dorsal series, gives the eight 

 dorsals we enumerate. The only discreijancy, in total numeration of cervical, dorsals, 

 aud sacro-lumbars, between his count (35) aud ours (34) is one cervical. There being 

 certainly but thirteen cervicals in our specimens, C. alba must possess one more cerv- 

 ical than C. .idnor, unless De Blainville miscounted. 



