454 Mt'sceUaneous. 



On the Megadactylus polyzelus of Hitchcock. By E. D. Cope. 



This genus was named by Hitchcock in his ' Supplement to the 

 Tchnology of New England,' p. 39, 18G5 ; the bones have been briefly 

 described in his ' Ichnology,' on p. 186. The remains were found, 

 in a more or less fragmentary condition, in the red-sandstone rot-ks 

 of the valley of the Connecticut, from the neighbourliood of Spring- 

 field, Massachusetts. They were found by WilUam Smith, while 

 engaged in superintending some excavations made at the armoury, 

 which required blasting. 



The remains consist of four caudal and one dorsal vertebrae, the 

 greater part of the left fore foot, with distal portions of the ulna and 

 radius, the greater part of the left femur, proximal end of left tibia, 

 greater part of left tibula, tarsus, and hind foot, including a tarsal 

 bone, perfect meiatarsus, proximal end of a second metatarsus, parts 

 of the distal end of a third, and parts and impressions of four pha- 

 langes. 



These fragments demonstrate the former existence in the region 

 in question of a typical form of the suborder or order Symphypoda 

 {Compsognaiha, Huxley), and one nearer the birds than any other 

 hitherto found in America. Its pertinence to this order is sliown 

 by the absence of the first series of tarsal bones, apparently (as 

 Gegenbaur has suggested, and as the structure of Lcelaj)s proves) in 

 consequence of their confluence with the distal extremities of the 

 tibia and fibula. This important character is apparently assumed 

 early in life in the present genus and in Compsognathns, and proba- 

 bly quite late in Oniithotarsus. In Compsognathus the additional 

 peculiarity of the persistence of but two carpal bones is presented, 

 which, according to Gegenbaur, should corres])ond with those of the 

 first row of ordinary Keptilia, wliile those of the second have disap- 

 peared. In MegadactgJus those of the first series are present, viz. 

 the radial and probably ulnar, and one of the second row, very 

 much reduced, oi)posite to the second metacarpus ; there is space 

 for a second one of the second series, but it does not appear in the 

 matrix, while the ulnar is probably lost. 



The bird-like tendencies of the Symphypoda have been indicated 

 above; and the very ornithic character of the bones of the present 

 form is also very marked. The walls of the long bones ai-e very 

 tbin ; in some places near their extremities almost as thin as 

 writing-paper. The vertebrae and ischia present the same thin walls ; 

 the structure of these walls is exceedingly dense. 



Prof. Cope next gives the special characters of the bones, whicli 

 are here omitted. He adds : — 



That animals of this genus made some of the tracks similar to 

 those of birds in the red sandstones of the valley of the Connecticut 

 there can be no doubt. It furthermore explains some problematical 

 impressions which are occasionally found with them. Tracks of an 

 animal resting in a plantigrade position, as indicated by the moulds 

 of two long parallel metatarsi, each terminated by thi-ee toes, are 

 accompanied by a peculiar, bilobate, transversely oval mark on the 

 middle line, some distance behind the heels. 



