122 Bulletin American Museum of Natural History. [Vol. XXXI, 



17. Perognathus fallax Merriam. Short-eared California Pocket 



Mouse. 



Female, San Bartolome Bay, March 14. 



18. Perognathus spinatus bryanti Merriam. Bryant Pocket Mouse . 



Four males, female, San Jose Island, April 1 ; 3 males, Espiritu Santo 

 Island, April 19. 



19. Perognathus baileyi insularis subsp. nov. Tiburon Island 



Pocket Mouse. 



In size and color about the same as P. penicillatus pricei. Skull in general rather 

 narrower; rostrum and nasals narrower; interparietal larger. Ascending branches 

 of supraoccipital narrower; maxillary arm of zygoma weaker. 



Type, No. 31846, male. 



Represented by 2 males and 1 female, Tiburon Island, April 13. 

 Measurements, average of three specimens: total length, 212; tail, 119; 

 hind foot, 27.3. 



20. Perognathus penicillatus goldmani subsp. nov. Goldman's 



Pocket Mouse. 



In general size and color about the same as P. baileyi; skull slightly smaller 

 and lighter; molariform toothrow shorter; inner side of parietal shorter. Named 

 for Edward A. Goldman. 



Type, No. 31845, male, Tiburon Island, April 13. 



Measurements of the type: total length, 171; tail, 90; hind foot, 23. 



21 . Perognathus spinatus nelsoni subsp. nov. Carmen Island Pocket 



Mouse. 



Compared with P. spinatus peninsula', the color is grayer and lacks the drab 

 brown effect seen in peninsula; general size similar, but tail slightly shorter — ■ 

 decidedly shorter than in bryanti. 



Type, No. 31855, male. 



Represented by 2 males and 1 female, Carmen Island, April 3. Named 

 for Edward W. Nelson, well known for his studies of Lower California 

 mammals. Measurements, average of three specimens: total length, 172; 

 tail, 93; hind foot, 24. 



Kangaroo rats are very abundant on Tiburon Island where there were 

 many tracts of level ground conspicuously marked with their burrows and 



