6 ELEMENTS OF COMPARATIVE ZOOLOGY. 



Morphology " (Holt), and Huxley's (t Anatomy of the Inver- 

 tebrates " (Appleton). Of these Lang's work is the most 

 detailed ; Huxley's is rather old ; Shipley's is the simplest. 

 The structure of. the vertebrates will be found in Wieders- 

 heim's " Comparative Anatomy of the Vertebrates" (Mac- 

 millan), Huxley's "Anatomy of the Vertebrates" (Appleton). 



The development of animals is discussed in the following 

 works : Balfour's " Treatise on Comparative Embryology " 

 (Macmillan), Korschelt and Heider's "Text-book of Em- 

 bryology" (Macmillan; one volume published so far), Hert- 

 wig's " Text-book of Embryology " (Macmillan), and 

 Minot's " Human Embryology" (Wm. Wood & Co). Bal- 

 four's treatise is a standard, but is rather old. Korschelt 

 and Heider deal only with invertebrates ; Hertwig and 

 Minot only with vertebrates. 



Good general zoologies are comparatively few. Under 

 this head are here included works which treat of the struc- 

 ture, development, and classification of animals. Possibly 

 the most widely used work is Claus's " Elementary Text- 

 book of Zoology,'* 2 vols. (Macmillan & Co.), which, how- 

 ever, is largely based upon European forms. The " River- 

 side Natural History, "6 vols. (Hough ton, Mifflin & Co.), is 

 more popular in style, and deals largely with American ani- 

 mals. Somewhat similar English works are the " Cambridge 

 Natural History," 10 vols. (Macmillan & Co.), and the 

 " Royal Natural History " (edited by Lydekker). 



The broader and more general biological principles, 

 without reference to classification and description of forms, 

 maybe found in Parker's "Elementary Biology" (Macmil- 

 lan) and Hertwig's " General Principles of Zoology" (Holt). 



Besides these there are a number of good works treating 

 of special groups of animals. The student at the seashore 

 of our New England States finds Smith and VerriU's " In- 



