514 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loe 



loincisive length 24.2; length of auditory bullae 5.2; crown length of 

 upper toothrow 4.8; least interorbital width 4.5; breadth of rostrum 

 at level of antorbital foramen 3.3; length of nasals 10.2. 



Remarks: In L. macculus the proportion of the least interorbital 

 width to the width of the rostrum ranges from 71.2 to 73.3 percent 

 (79.7 to 81.6 percent in striatus) and the proportion of the length of 

 the nasals to the total length of the skull ranges from 37.8 to 38.9 

 percent (36.0 to 36.7 percent in striatus). It may be noted that in the 

 first proportion the size dijfference between L. macculus and L. striatus 

 is apparent, but in the second proportion, that of nasals to total length 

 of skull, the ratio is reversed, which shows that the nasals, even though 

 measuring shorter in macculus, occupy more of the total length of the 

 skull than in striatus. 



These two proportions appear to hold good on other specimens of 

 these two species in both the U. S. National Museum and the British 

 Museum collections so that they perhaps will be valid for critically 

 distinguishing the two species where they occur together. 



In general, macculus is a smaller animal than is striatus. In the 

 former the hind foot usually measures less than 26 mm., while in the 

 latter the hind foot is usually larger. 



Lemniscomys striatus massaicus (Pagenstecher) 



Mus {Lemniscomys) barbarus L. var. Massaicus Pagenstecher, Jahrb. Hamburg- 

 ischen Wiss. Anst., vol. 2, p. 45, 1885. (Lake Naivasha.) 



Specimens Examined: Thirty, from: Gilo, Imatong Mountains, 

 11 (4, MCZ) ; Torit, 2; Nimule, 5 (3, MCZ) ; Katire, 9 (AICZ) ; Mag\ve, 

 2 (AICZ); Talanga Forest, Imatong Mountains, 1 (MCZ). 



Measurements: An adult male and an adult female from GUo, 

 Imatong Mountains, respectively measure as follows: Length of head 

 and body 123, 107; length of tail 130, 130; length of hind foot 28, ?; 

 length of ear 11, 12; greatest length of skull 29.4, 29.0; condyloincisive 

 length 26.5, 26.2; length of auditory bullae 5.9, 5.0; crown length of 

 upper toothrow 4.9, 5.1 ; least interorbital breadth, 4.8, 5.0; breadth of 

 rostrum at level of antorbital foramen 3.5, 3.8: length of nasals 10.6, 

 10.8. 



Remarks: This species can easil}^ be confused with L. macculus. 

 There are, however, several pronounced cranial differences between 

 the two species. In the present series, the proportion of the least 

 interorbital width to the width of the rostrum is greater; and the 

 proportion of the length of th(; nasals to the total length of the skull 

 is less in the larger species striatus. 



