644 Recently published Ornithological Works. 



proceeds to explain on a Mendelian hypothesis, for the 

 details of which we must refer the reader to the memoir 

 itself. 



The second paper in the list gives a detailed account of 

 the passage of the hen's egg down the oviduct, and of the 

 exact portioiis of the oviduct where the egg acquires its 

 albumen of two varieties, its shell-membrane and its shell, 

 and of the time taken to acquire these various coverings. 



The last paper deals with the origin of the fat found 

 deposited among the interstitial cells of the testis and ovary 

 of the fowl, and it is concluded that this is a part of the 

 metabolized fat from the food which is carried to the testis 

 and there directly deposited. 



Ridgway's Birds of North and Middle America. 



[The Birds of Nortli and Middle America : a Descriptive Catalogue, 

 etc. By Robert Ridgway. Part vi. (of Bulletin no. 50 of the United 

 States National Museum). Pp. xx+882; 3(3 pis. Washington (Govt. 

 Printing Office), 1914, 8vo.] 



It is just two and a half years since Mr. Ridgway com- 

 pleted the fifth part of his monumental work on the birds 

 of North America, and we have now received a copy of 

 Part VI., which was issued from the press on the 8th of April 

 last. It contains descriptions of the Picarian Birds, 

 including the Woodpeckers, Barbets, Toucans, Puff-birds, 

 and Jacamars ; of the Anisodactylse, including the King- 

 fishers, Todies, and Motmots ; of the Nycticoracise, including 

 the Goatsuckers; and of the Owls. The Cuckoos and 

 Parrots have had to be excluded, and will appear in the next 

 Part. As it is, the present volume consists of 882 pages. 



For those who are not acquainted with Mr. Ridgway's 

 work, it may be added that full descriptions, not only of each 

 subspecies and species, but of the higher groups (genera, 

 families, etc.), are given, and that all the species occurring 

 in North America, from the Arctic to the Isthmus of 

 Panama, as well as those of the West India Islands and 

 Galapagos, are included. A series of 36 plates of the 

 structural characters of each genus is a most useful addi- 

 tion and a great assistance to the working ornithologist. 



