BihUographical Notices. 261 



as an example of this latter feature only the very first essay in the 

 volume, that on the migrations of birds. Then, as regards some moot 

 points of natural history, the student will do well to turn from the 

 pages of his "Wallace" or "Darwin" and compare what they have said 

 with what Blackwall here tells us concerning the notes and instincts 

 of birds in reference to the question so often raised as to their being 

 innate or acquired. The Cuckoo furnishes the subject of a long and 

 interesting article ; and when to this we add that other pages are 

 specially devoted to the problems of birds becoming torpid, deserting 

 their young (like the Swallow), and diving, as do many aquatic species, 

 we have, while omitting to mention some shorter essays, said enough 

 to show that the interests of the ornithologist have not been neglected ; 

 and turning next (at page 184) to the growth of the Salmon and of 

 the Sewin, we may make the same remark also in reference to the 

 student of fishes. 



Our space will only suffice for mentioning that the remaining 

 pages are devoted chiefly to observations upon insects and Spiders, 

 in which last group we encounter Blackwall upon a field of inquiry 

 that, in the pages of this Journal and elsewhere, he may be said to 

 have made peculiarly his own. If any one asks himself, how the 

 gossamer spider manages to float through the air, or how the geo- 

 metric species contrive to make their nets, he wiU turn in vain to 

 many a goodly-looking volume of natural science or of comparative 

 anatomy for any thing approaching an intelligible or satisfactoiy 

 answer. But here, in Mr. BlackwaU's volume, the reader will find a 

 solution of much of, and more than, what he is in search after. 

 In many cases, too, both observation and direct experiment have been 

 brought to bear upon the points immediately under investigation ; 

 and it is by this double process that our author determines the means 

 by which various animals adhere to or move upon polished vertical 

 surfaces, and whether the poison of spiders is as fatal instantaneously 

 to their prey as it is commonly supposed to be. A valuable paper 

 on the structure and economy of spiders concludes a volume of no 

 less than twenty-five separate essays, out of which we have, for the 

 purpose of this cursory notice, made mention only of a few. To the 

 reader we will only add, get the book itself. As a contribution 

 to our zoological literature of an independent kind BlackwaU's 

 pages stand alone — a type the Uke of which we would, in this age of 

 improved biological speculation, gladly see more of. 



On some Remarkable Forms of Animal Life from the Great Deep off 

 the Nonvegian Coasts. — I. Partly from the Posthumous Manu- 

 scripts of the late Prof. Dr. Michael Sars. By George Ossian 

 Saks. Christiania, 1872. 4to, pp. 82, with six copper plates. 



This work is written in English, with the characters of the genera 

 and species in Latin. It contains the descriptions of: — two species of 

 Polyzoa (1. lihahdopleura mirabilis, 2. Flustra abt/ssicola) ; two 

 Conchifera(l. Yoldia obtusa, 2. Pecchiolia abyssicola) ; three Cepha- 

 lophora (1. Dentaliuui agile, 2. Triopa incisa, 3. Gonieolis ii/pica) ; 



