16 FOSSIL REPTILIA OF THE 



more abruptly defined outer half of the surface from the inner anteriorly more convex 

 half. The anterior surface of the fore part of the shaft of the humerus, here 

 preserved, is impressed by longitudinal reticulate markings. The total length 

 of the humerus, according to the proportions of the length of that bone to the 

 breadth of its proximal articular surface in Pterodactylus suevicus* would be 10i 

 inches. 



Fig. 9 shows well the minutely punctate surface of the articular head of the 

 humerus ; the portion of the fore part of the shaft preserved with this shows that the 

 fine reticulate markings are limited to a short distance below the head, and that the 

 rest of the outer surface of the shaft here preserved is smooth. The extent of the 

 base of the outer plate or process is 1 inch, the long diameter of the articular surface 

 of the head being 1 inch 3 lines. 



The fragment of the head of the humerus (Tab. Ill, fig. 10) is remarkable for 

 the well-defined ridge bounding the anterior convex part of the articular surface. 



The proximal end of the smaller humerus (fig. 11) includes nearly two inches of 

 the shaft, of which a front view is given in fig. 12, and a back view in fig. 13. The 

 base of the outer process (g) shows the same proportion to the long diameter of the 

 head, as in fig. 9. The fractured surface along the opposite side of the shaft (/) seems 

 to show that this border had been produced into a ridge or plate, as in Ptero- 

 dactylus sylvestris. The back part of the shaft between these plates is concave 

 transversely, but rather convex lengthwise ; the opposite conditions prevail on the 

 fore part of the bone. Here, towards the base of the outer process, is a small, 

 apparently pneumatic, oblong foramen. 



The smaller proximal end of humerus (figs. 14 and 15), shows a larger proportion 

 of the process (/) which extends the bone in that direction beyond the articular head. 



All these specimens show that, in the Pterodactyles from the Green-sand, there is 

 a plate or process with a shorter base, extending close to the articular surface of the 

 head of the bone, and that there is a plate, with a larger base, extending farther from 

 the articular head at the opposite side of the bone. 



The fragment (figs. 1, 2, and 3, Tab. IV) shows part of the articular extremity 

 of one of the long bones of the wing. The articular surface has been partially 

 divided into what might be called, were they entire, two condyles (a and b). The 

 most perfect of these divisions shows a slightly convex surface (figs. 1 , and 2. a, a,) 

 occupying its major part, and a small well-defined flat surface (figs. 1, and 3, c,), placed 

 obliquely. So much of the other division as is preserved likewise shows two facts 



* See the plate in Quenstedt's ' Memoir,' above cited. 



