Cope.] -^16 [AprillS, 



of Belodon, but, like the humerus, is characterized by a relatively small 

 diameter of the shaft. The outline of the head is wide-reniform, the 

 shallow concavity posterior. The articular surface descends on each side 

 of this concavitj'', giving a convex outline to the superficial layer of the 

 posterior face of the bone. Anteriorly the articular region projects fur- 

 ther to one side than to the other, perhaps leaning to the external side. 



3Ieasurements of the tibia. M. 



- - ... ( anteroposterior (middle).. . .073 



Diameters of head of tibia < . ^_^ . „„ 



I transverse 107 



^. r. ■. n (anteroposterior 032 



Diameters of shaft i ^ ^,o 



( transverse 04o 



The distal end of the fibula is robust. One face of the shaft is concave ; 

 the opposite one is convex. On the concave side, one-half the bone pro- 

 jects distad abruptly beyond the other half. On the convex side, the 

 edge of the articular extremity winds obliquely from the one level to the 

 other. This indicates the fact that the articular face forms a segment, 



equaling three-fifths, of a spiral. 



M. 



T^. , Til 1 j.^1 1 (transverse (axial) 080 



Diameters distal end of fibula -^ . ' .,„ 



(anteroposterior 048 



The calcaneum has the form usual in crocodiles, and especially in Belo- 

 dontidtTC. It is wider and flatter than in any species known to me. The 

 external rim extends from the anterior to the posterior extremities, and 

 is quite expanded. The distal extremity is pyriform, and its recurved 

 edges bound posteriorly a deep fossa on both the superior and the inferior 

 aspects of the bone. These fossse' are continuous by the open concavity 

 of the internal margin. This margin is flared inwards in front by its 

 truncate anterior face, which bounds the astragaline fossa behind. The 

 latter is wider than deep. The articular surface is divided into two planes ; 

 a narrow interior for the tibia, and a wider exterior for the fibula. Both 

 are convex anteroposteriorly, and nearly plane transversely. 



Measurements of calcaneum. M. 



, , . . T . (longest 90 



Anteroposterior diameters \ ° , ,- e ko 



( at astragaline fossa 52 



( anteriorly 50 



Transverse diameters \ median (greatest) 91 



i posterior 74 



The dermal bones are of three types, of each of which I select an ex- 

 ample. They are all, or nearly all, furnished with a prominence of the 

 superior surface, which is more or less compressed, and which is abrupt 

 at one face, and produced into a keel at the other extremitj^ in the direc- 

 tion of the axis of the bone. All the bones preserved are unilateral in type. 

 The simplest form is oval-parallelogrammic, with a low obtuse median 

 keel, which rises at one extremity into a moderately compressed knob. 



