148 
JOURNAL OF MAMMALOGY 
Cabrera, Angel. Genera Mammalium. Monotremata, Marsupialia. Ma- 
drid, Museo Nacional de Ciencias Naturales, pp. 1-177, pis. 1-19, many figures in 
color. 1919 (Received in Washington October 6). 
The appearance of the first part of Cabrera’s Genera Mammalium marks the 
beginning of a work which, if completed in the same manner that it has been 
begun, will be the most important publication on mammals since Trouessart 
issued his Catalogus twenty years ago. The author has had long experience in 
the analytic study of his subject; he now shows his ability in synthesis. Those 
who are acquainted with the literature of mammals will appreciate the degree 
to which this combination of qualities is rare. 
“The plan which I have followed,” Mr. Cabrera writes in his preface (freely 
translated), “is the same as that of the well known Genera Insectorum of Wyts- 
man, a plan which has appeared to me the most satisfactory on account of its 
conciseness and clearness. In imitation of the procedure followed in this monu- 
ment of entomological literature I omit keys to the species, limiting myself to 
enumerating these alphabetically and distinguishing them by serial numbers; 
the same is done under each species for the subspecies, which are designated by 
Greek letters. I recognize that my book is, rather than the result of personal 
investigation, a simple work of compilation. If there is anything good or useful 
in it this will be the material which I have taken from others. My task, more 
mechanical than anything else, has merely been to assemble this material. The 
errors which may have slipped in will, I hope, be pardoned by the reader in view 
of the abnormal conditions which humanity is subjected to at this time and which 
have made it difficult to procure certain references and details that would have 
contributed toward greater completeness.” 
The text is entirely in Spanish. It consists of a series of diagnoses and keys 
(strictly dichotomous and clearly expressed; I have not yet had the opportunity 
to test them with specimens), covering all groups from order to subgenus. Syno- 
nymies and distributions are given under genera, subgenera, species and sub- 
species; a bibliographical paragraph is included in the account of each family. 
Other subjects formally treated are: history (under families), habits (under 
families), reproduction (under families), paleontology (under families), types 
of recognized genera and subgenera, and derivation of the accepted generic and 
subgeneric names. Mr. Cabrera’s work has been done with great care, thorough- 
ness, and skill, so that errors, typographical and other, are conspicuously infre- 
quent. The omission may be noted of Leucodidelphis (von Ihering, Revista Mus. 
Paulista, vol. 9, p. 347, 1914) under the genus Didelphis and of the very important 
Eodelphis (Matthew, Bull. Amer. Mus. Nat. Hist., vol. 35, p. 477, July 24, 1916) in 
the account of the paleontology of the family Didelphidoe. Three new genera are 
described: Minuania (type, Didelphis dimidiata Wagner), Holothylax (type, 
Didelphis opossum Linnaeus), and Amperta (type Choetocercus cristicauda Krefft). 
The plates were drawn by the author. While the figures of skulls and teeth seem 
to be entirely satisfactory the reproduction of the colored drawings leaves much 
to be desired; obviously in most instances justice to the originals has not been 
done. 
There are three features in the plan of the book which might be altered to the 
advantage of future parts. The scale of reduction or enlargement could be 
indicated by a symbol placed after the number of each figure on the plates, a table 
