THE MICROSAURIAN FAMILY AMPHIBAMID^. 



131 



Measurements of Amphibamus grandiceps Cope. 



Collection of Mr. L. E. Daniels, of Rolling 

 Prairie, Indiana: 



mm. 



Entire length of specimen 62 



Posterior width of head 15 



Length of head 15 



Posterior height of skull 3 



Length of orbit 5 



Width of orbit 3.5 



Interorbital width 4 



Width of skull in front of orbits 11 



Width of skull just back of orbits 16 



Length of presacral region of the vertebral 



column 30 



Length of tail 13 



Length of fore limb 13.5 



Length of humerus 4 



Length of radius and ulna 3 



Length of right hand as preserved 3.5 



Length of rib along curve 5.5 



Length of hind limb 17 



Length of ilium 4 



Length of vertebral centrum 1.75 



Length of portion of scapula (?) preserved. 4.5 



Length of foot 6.5 



Width of impression of body midway 16 



No. 794 (1234), Yale University Museum: 



mm. 



Length of skeleton 67 



Length of skull 15 



Posterior width of skull 15 



Depth of tympanic notch 4 



Width of tympanic notch 6 



Long diameter of the orbit 7 



Transverse diameter of the orbit .5.5 



Interorbital width 4.5 



Diameter of pineal foramen .75 



Length of cervical series of vertebrae 9 



Length of dorsal series 35 



Length of caudal series 13 



Length of a centrum of the dorsal series. ... 1.5 



I./ength of dorsal rib 3.5 



Length of arm 20 



Length of humerus 7 



Length of radius and ulna 4 



Width of carpal space 3 



Length of third digit 5 



Length of leg 25 



Length of ilium 3 



Length of femur 9 



Length of tibia and fibula 5 



Length of carpal space 4 



Length of I st digit 3 



Length of 2d digit 4.5 



Length of 4th digit 7 



3 ventral scutelloe in i mm. 



Amphibamus thoracatus Moodie. 



MooDiE, Proc. U. S. Nat. Mus., 40, pp. 431-433, fig. 2, 191 1. 



Moodie, Kans. Univ. Sci. Bull., vi. No. 2, pp. 347-349, pi. 5, fig. 2, 1912. 



Type: Specimen No. 4306, U. S. National Museum. 



Horizon and locality: Mazon Creek shales, near Morris, Illinois. 



The type is a part of the collection of Mr. R. D. Lacoe, in the U. S. National 

 Museum. The fossil is very poorly preserved, but the remains are to be seen on both 

 halves of the nodule, so that considerable can be made out as to its structure. 



The chief diagnostic characters which will at once distinguish the species are the 

 elongate arm, large interclavicle, shape of the vertebra, and triangular skull. 



The portions of the animal which are preserved are the impression of the skull 

 with one orbit, the right humerus and radius with portions of others, and traces of 

 ventral scutellae. These remains are so intermingled with the remains of plants 

 that it has been quite difficult to distinguish bone impression from plants. This, 

 however, has been done by whitening the fossils with ammonium chloride, when the 

 texture of the fossils serves to distinguish the one from the other. Parts of the plants 

 have been converted into galena and kaolin, as have also parts of the bones, so the 

 task has been rendered doubly diffictilt. There can be no doubt, however, that the 

 observations recorded below are correct. The position of the arm in relation to the 

 pectoral girdle and the position of the girdle in relation to the skull impression first 

 called attention to the possible presence of a fossil amphibian. 



There is little to be said of the skull. It is merely an impression in the nodule. 

 It is triangular in form, with the snout an acute angle. The angle is, however, exag- 

 gerated by the compression to which the fossil has been subjected. The right side of 

 the skvill lies over a portion of some plant. The animal is preserved on its back, so 

 that this gives a good opportunity for the study of the pectoral girdle, which is par- 



