1896.] NATURAL SCIENCES OF PHILADELPHIA. 527 



at the upper anterior base of ear. There is a large white spot 25 

 mm. long and 10 ram. wide reaching around lower base of ear to 

 angle of jaw, and the ears are broadly tipped and fringed with 

 white ; both these characters not being shown in Milne-Edwards 

 plate of imhausi. 



Cranially, the Smith specimen differs specifically in its narrow 

 interorbital width, the less produced expansion of the occipital re- 

 gion beyond posterior line of the interparietal and the almost com- 

 plete suppression of the forward extension of the squamosal. In the 

 type of imhausi this bone forms an exterior rectangular keystone 

 about 3 mm. square, at the junction of the frontal, parietal and 

 jugal bones, distinctly separating the superior wing of the jugal 

 from contact with the lateral wing (postorbital process) of the 

 frontal ; in the Smith example these bones touch each other, being 

 only separated anteriorly by a slender, irregular extrusion of the 

 squamosal 5 mm. wide and 2 mm. long. 



The dentition of smithi, making allowance for the difference in 

 age, appears to be almost identical with Edwards' figures" of imhausi^ 

 except that the posterior upper molar lies wholly outside the median 

 longitudinal axis of the anterior molars. In the latter the nasals 

 are broader posteriorly than anteriorly, these proportions being re- 

 versed in smithi. In imhausi the postpalatal notch is opposite ante- 

 rior base of posterior molar ; in smithi it only reaches the middle of 

 that tooth. The paroccipital processes in smithi are directed forward 

 against the audital bullse ; in imhausi they are directed backward 

 and separated from the bullse by a distinct space. The mandible of 

 smithi, while exactly the same length as that of imhausi, is very 

 much more slender, the greatest breadth of the latter being 4 mm. 

 greater. The three recorded specimens'^ all came from a tract on the 

 Red Sea north of the 15th parallel ; smithi was taken on a mount- 

 ain 5,000 feet high, in the Indian Ocean-drainage about 700 miles 

 southeast of the most southern recorded locality of an imhausi spe- 

 cimen. 



For an account of the capture of the specimen and of the nature 

 of its habitat, the reader is referred to Dr. Smith's narrative. 



28. Acomys spinosissimus Peters. Peters' Acomys. 



A series of Spiny mice, taken between the 12th of March and the 

 17th of April, 1895, and preserved in alcohol, seem to correspond 



" Milne Edwards' type was purchased alive at Aden. Its locality was ap- 

 parently near that of the others, as they are regarded as the same species. 



