314 Recent Literature. [April, 



obliterating the structure of the original notochordal cells, until 

 finally the notochord consists of a series of clear spaces separated 

 by hyaline partitions. These vacuoles are traceable also in tuni- 

 cates, and in the teleosts or bony fishes. 



In conclusion, we have to say that Hatschek has given to the 

 world a most valuable addition to its stock of embryological 

 knowledge. 



Trouessart's Catalogue of Recent and Fossil Mammals. 1 — 

 Catalogues of animal forms are as necessary to a student of 

 zoology as are catalogues of books to the frequenters of a library, 

 or directories to dwellers in cities. No zoologist can carry in his 

 brain, ready at an instant's notice, the accepted name, synonymy, 

 etc., of all the species included in the department he specially 

 studies, and thus such works as Gray's Hand-List of Birds, and 

 the present are great boons to him; they save him hard work, 

 and leave him free to exercise his mind upon purely scientific 



Dr. Trouessart's catalogue, which has already progressed to 

 the completion of the Primates and Rodentia promises to be to 

 mammalogists what Gray's Hand-List is to ornithologists, with 

 the added recommendation that it contains also all known species 

 of fossil mammals, and will therefore prove equally useful to the 

 palaeontologist. 



The classification adopted is to a great extent that of modern 

 authors with the addition of the orders proposed by Professor 

 Cope, and is based upon the structure of the feet and teeth, ex- 

 cept in the division of all mammalia into the universally accepted 

 sub-classes Monodelphia (placental) and Didelphia (non-placental). 



The Prosimiae (Lemurs) are separated as an order from the 

 Simiae; Cope's order Bunotheria, with four extinct sub-orders 

 ( Mesodonta, Creodonta, Tillodonta, Tccnioilontn), and one recent 

 sub-order (Insectivora), is placed among the Secundates, or ungui- 

 culates; the Toxodonta are considered a sub-order of Rodentia, 

 and the Zeuglodonta has the same rank among the Pinnipedia. 

 The line of hoofed animals or Ternates is concluded by the Am- 

 blypoda, with two sub-orders, Dinocerata and Pantodonta ; the 

 porcine group is separated as a sub-order from the ruminants, 

 and the order Sirenia is intercalated between the Edentata and 

 the Cetacea. The last mentioned three orders form the group 

 Homodonta, of equal rank with the Heterodonta, which includes 

 the remaining monodelphian orders. 



The catalogue gives, besides genera, sub-genera, and species, 

 the habitat, the synonymy, and all varieties on which species 

 have been founded. When these varieties are merely local, or 

 perhaps based on individual characters, they are marked with the 



1 Catah;ue des Mammifires Vivants et Fos silts. Par le Dr. E. L. TrouessART. 



