674 JfE. "Vr. H. HAEDAKEE ON A FOSSIL-BEARIXG HOEIZOX [DeC. 1912. 



Measurements. 



He. 



ICHXIUM ACEODACTTLUM 



Pahst. 



Fore foot: 

 1 Length 



cm. cm. 



0-4 0-6 



0-5 0-7 



1 0-2 



0-3 



f 0-4 



0-4 



0-3 



cms. 

 8-0 

 6-3 



2-5 « 

 30 

 3-5 

 4-5 

 3-3 



Breadth 



1st toe 



211(1 toe 



3rd toe 



4th toe 



5th toe 





Hind foot; 



0-4 0-65 

 0-5 075 

 i 0-2 

 j 0-3 

 1 0-4 

 j 0-4 

 i 0-3 



0-9 

 0-7 

 0-4 

 4-5 

 4-5 

 5-5 

 3-5 



Breadth 



1st toe 



2nd toe 



3rd toe 



4th toe 



5th toe 





Track-measurement I ") 

 Track-measurement II ) 

 Width of track . ... 



about 1 cm. each. 

 1-3 



(13-0 



llTb 



18-0 





Fig. 2^,-Type H, 

 from Hamstead 

 (natural size). 



Type He is distinguished from the other Hamstead tj'pes, the 

 fore aud hind feet of which are markedly unequal in size and their 

 gait alternate, by a close approximation in size 

 of the feet and a non-alternate but opposite 

 gait. The footprints are also evenly spaced in 

 the track (see fig. 28). 



In these respects they agree with footprints 

 from the Upper Rothliegende of Thuringia, 

 named by Prof. Pabst Ichninrn acrodactylum . 

 These specimens show footprints far larger than 

 those of He ; but there is a general agreement 

 in shape, relative size, and spacing of the feet. 

 Pabst's description of his species is as follows : — 





^% 



I 

 I 

 I 

 I 



ftfl*^ 



' Single footprints, with Jong narrow ball with dis- 

 tinctly max-ked heel. Five-toed. The toes long, conical, 

 each tapering, and protected by a claw. The fifth toe 

 spread out, the fourth the longest, the first the shortest. 

 The length of the footprint about 2 cms. greater than 

 its width. The fore footprints rather smaller than 

 those of the hind feet. Grait not alternating.' (Op. cif. 

 pp. 433-34.) 



In the Hamstead specimen I can see no indi- 

 cation of a claw being present ; but the descrip- 

 tion in other respects will answer for the two. 

 The resemblance in shape, equality in size 

 of the footprints of the fore and hind feet, 

 and in particular the unique opposite and 

 equally spaced-out gait, lead me to class this type with /. acrodacty- 

 lum. despite the great disparity in size. The comparison between 



/ 



II 



