62 DAVIDSON BLACK 



Most of the work in coii'nection with the literature bearing 

 upon the subject of this paper was carried out in the Ubrary of 

 the University of Toronto, and it is a pleasure to acknowledge 

 my indebtedness to Profs. B. A. Bensley, J. J. R. Macleod, and 

 J. J. Mackenzie, of that institution, for their courtesy in placing 

 the facilities of their departmental libraries at my disposal. I 

 am also indebted to Prof. H. M. Evans for similar courtesies 

 extended to me at Berkeley, California. 



Damonia subtrijuga, which is here desciibed in comparison 

 with other reptiles, is a member of the cosmopolitan family 

 Testudinidae.' This little tortoise is an Asiatic form occurring 

 in Siam, Cambodia, and Java (Flower, 15). It is almost wholly 

 aquatic in its habit and carnivorous in its diet.- 



The motor nuclei and roots have already been studied and 

 reconstruction charts have been made on the following reptilian 

 types: Chelone mydas. Alligator sclerops,^ Boa constrictor, and 

 Varanus salvator (see especially Kappers, 31, 32). These charts 

 are reproduced for comparison in the present paper in figures 

 11 and 12, pages 82 and 83. 



MOTOR ROOTS AND NUCLEI IN DAMONIA SUBTRIJUGA 



Nerve XII 



The hypoglossal roots in Damonia arise from a nucleus of 

 large multipolar cells situated in the dorsal part of the rostral 

 end of the gray reticulum of the cervical motor column. The 

 majority of the cells comprising this nucleus lie rostrad of the 

 exit level of the first hypoglossal • rootlet. They form a cell 



1 Nomenclature according to Boulenger (6). Previous to the hitter's work 

 on the chvssification of Chclonia, Giinther (23) has described this form under the 

 iiame Emys macroccphahi, while Gray (22) had recorded its occurrence under 

 the name D. macrocephala, giving as synonyms Geolemmys nacrocephala, Gray, 

 and Emys trijuga, Mas. 



- In captivity the animals observed by Flower (1. c.) refused all food except 

 molluscs. 



3 It is possible that the generic name Alligator has been applied to this speci- 

 men in mistake for Caiman. C. sclerops has a wide distribution from southern 

 Mexico to northern Argentina and resembles Alligator in most features (Gadow, 

 13. and Cope, 10). 



