1 9 4 Bulletin A merican Museum of Natural History . [ Vol .XXII, 



44 of Didelphis, 20 of Tatu, 23 of Tayassu, over 100 of Odocoileus, 

 14 of Lynx, 24 Ocelots, 5 Jaguars, and corresponding series of the 

 common Rodents and Bats. The collection numbers altogether 825 

 specimens, representing 41 species. 



As in his previous collections, Mr. Batty has usually taken four 

 measurements of most of the specimens, namely: (i) Head and body; 

 (2) tail vertebrae; (3) hind foot (measured to the end of the longest 

 toe, and hence not including the claws) ; (4) ear, measured from the 

 notch, and in some cases also from the crown. The total length, 

 as given in the following pages, is made up (for convenience in com- 

 parison with the usual 'total length') by adding the collector's first 

 two measurements. He was obliged to take his measurements in 

 inches and fractions (usually i6ths), owing to the early loss in the 

 field of his metric rule, so that it has been necessary to reduce them 

 to the metric system. In the case of the larger species, such additional 

 measurements were taken as would be required by the taxidermist 

 in mounting the specimen, but they are here omitted as being not 

 especially useful. 



In the following measurements of skulls, total length is the greatest 

 length of the skull ( =condylo-basal length of Thomas) ; basal length 

 is the distance from the inferior border of the foramen magnum to 

 the inner base of the middle incisor (= basilar length of Hensel and 

 Thomas) ; occipito-nasal length, used only for the species of Lepus, 

 is to be taken in its literal sense 1 occipital crest to front border 

 of nasals; palatal length, from inner base of incisors to palatal notch 

 (^palatilar length of Thomas). Other measurements, when re- 

 quiring explanation, are explained as used. 



The measurements are, of course, always in millimeters, unless 

 otherwise stated. 



i. Marmosa sinaloae Allen. 



Nine specimens, Escuinapa, Jan. 8 and 28, Feb. 5 and 6, June 

 24, July 3, 4, 15, and 17. 



1 Occipito-nasal length has been used for "the greatest length of the skull," or for the 

 "length on median line from occipital crest to front of nasals," by the same authors on different 

 occasions. "Basal length" and " basilar length" have been defined by one and the same 

 author, in different connections, to mean : Basilar length, (i) occipital condyle to incisor, or 

 more explicitly, from one of the occipital condyles to the posterior edge of the alveolus of the 

 middle incisor of the same side; (2) from condyle to front border of premaxilla. Basal length, 

 from basion (anterior margin of foramen magnum) to gnathion (front edge of premaxilla) ; 

 greatest basal length, condyle to front 9f premaxilla. In cases (which are many) where these 

 terms are used without definition, there is always uncertainty of meaning. I find I have myself 

 in common with many other writers, used the same terms in slightly different senses in papers pub- 

 lished at different times. Mr. Oldfield Thomas's recent 'Suggestions for the Nomenclature of the 

 Cranial Length Measurements and of the Cheek-teeth of Mammals' (Proc. Biol. Soc. Washing- 

 ton, Vol. XVIII pp. 191-196, Sept. 2, ^1905), are therefore especially welcome, and should 

 Inu S 2,i edll y p tne uss of a definite and uniform system of terms among all mammalogists, 

 Inat Ihomass terms are not adopted in this paper is due to the fact that most of the meas- 

 uremsnts had baan taken and a large part of the manuscript prepared before his excellent paper 

 appeared. 



