108 



THE EXTINCT BATRACIIIA, REPTILIA 



n. 



Lin, 



5 



8 



6 





2 



11 



2 



5 



2 



5* 



1 



G" 



Length in the axis, 



" laterally " 

 Transverse diameter of proximal end, 

 Vertical !' " " 



Transverse diameter of distal end inferiorly, 

 Vertical diameter at middle of trochlea, 



The phalanges and tibia figured by Leidy in Cretaceous Reptiles, tab. xvii., 8-11, differ from those from Barnes- 

 boro, and, I suspect, belong to another species. Indeed these portions are so uncharacteristic in Reptiles that they 

 cannot be certainly assigned to the genus Laelaps. 



Whole Hind Limb. — The femur and tibia together measure 05.50 inches. A method of estimating the 

 length of the metatarsus is by comparison with that of Hylaeosaurus, as described by Prof. Owen. The distal 

 extremity of the inner metatarsus in L. macropus (fig. 13) is much like the same in Hylaeosaurus, while the proximal 

 of the outer is like that of Megalosaurus as figured by Owen, so that I estimate their length together to have been ten 



inches. The transverse extent of the tibia in the same species is four inches. The latter measurement in L. aqnil- 



i 



unquis being seven inches, it gives as the whole length of the metatarsus eighteen inches. 



The length of the tarsal region may have been five inches. 



The longest digit most probably embraced as in the crocodile, four phalanges. None of the eight phalanges of 

 the genus which have been preserved arc of shortened form like the penultimates in the Palaptoryx etc., but though 

 from different portions of the toes are all well represented by those of the crocodile. I am disposed therefore to be- 

 lieve that the toes were long, and to attribute to the longest a length of twenty-one inches, measuring the chord of 

 the ungual phalange. 



These measurements give for the total length of the extended hind limb, ton inches more than eight feet. This 

 is probably greater in comparison with the total length than in Iladrosaurus, where the elements beyond the tibia 

 are comparatively short. The length of the hind limb in Iladrosaurus foulkii was probably a little over nine feel,. 



Pubes. — Each pubis has a gentle sigmoid flexure and a subti -igonal section. They are flattened at the inner 

 extremity, and dilated, with a margin at right angles to the shaft ; the whole of this extremity is not preserved. It 

 is hollow, while the shaft is dense and heavy. Length 18.5 inches. I am disposed In regard these slender bones as 

 pubes also, because they are homologous with similar bones in Iladrosaurus, whose isehia we are probably in posses- 

 sion of, which are quite different. Moreover the pubes of Iladrosaurus would not support the animal's weight as 

 isehia, nor would they permit any lateral motion of the caudal column. The tail of Laelaps probably possessed such 

 a motion, and if the ilium be similar to that assigned to Megalosaurus by Huxley, the long palies if placed in the 

 position of isehia would interfere with such motion. 



The elongate isehia of Stenopelix are not dissimilar to those of Laelaps, but in the more nearly allied Compsogna- 

 thus the pubes are the more elongate. 



? Ilium.— Huxley's statement that the so-called coracoid of Megalosaurus is the ilium, loads us to anticipate a 

 similar form for that of Laelaps. In Megalosaurus it is a semidiscoid plate, the superior margin forming an arc, the 

 inferior furnishing the acetabular and articular surfaces. It has not the elongation of that of the Orfhopoda, hut is 

 thinner and lighter. 



? Sternum. — Very broad, thin, plate like bones have been on three occasions found with Goniopod Dinosauria. 

 One of these was found with the New Jersey, the other with the Mississippi Laelaps. The Mississippi specimen is 

 18.6 inches long, and presents a, thickened margin with convex outline on one side, and thins away to a thin edge at 

 a width of 4 in. 5 lin. One side of this plate is convex, the other concave, and the ossification radiates from the mid- 

 dle of the thickened margin in every direction. There are no traces of contact with diapophyscs of a, sacrum. The 

 New Jersey specimen, found with the other remains of Laelaps aquihmquis, is merely a piece broken from the thick- 

 ened margin of a similar, though smaller bone measuring some 4.5 in length and 1.75 in width. 



The form of these pieces reminds one of the thiii concave anterior expansion of the ilium in gallinaceous and 

 other birds, or if sternal, of the xiphisternal element. 



