246 REVIEWS NATURAL, HISTORY. 



Chelonioidse and Spharsididse, whilst the latter is regarded by him 

 as including seven families. V/e have then an examination of all the 

 particulars in the organization of the family. Sections follow on their 

 growth. Psychological developement, geographical distribution, and 

 fossil history. The characters of the sub-orders are then more partic- 

 ularly considered, which leads us to the conclusion of the first chapter. 

 Desiring to bring under the notice of our readers any peculiar and 

 striking opinions of our author, whether or not we are able at once to 

 receive them in their whole extent, we quote the follomng passage 

 from the concluding section : 



" Sueh a method " [full anatomical illustrations of structure in Zoological works] 

 " will, in due time, relieve our science of all the exaggerations respecting homolo- 

 gies, with which it has of late been incumbered. As soon as it is understood that 

 the great branches of the animal kingdom are characterised by different plans of 

 struetvire, and not by peculiar structures, we shall have fewer of those unsuccess- 

 ful attempts to force every peculiarity of every type into a diagram, by which, 

 renouncing almost entirely the study of the wonderful combinations of thought, 

 which are manifested in the endless diversity of living beings, authors %ubstitute 

 for them a dead formula of their own making. Having once imderstood, for in- 

 stance, what constitutes the plan of Vertebrates, Ave shall be prepared to find it 

 executed in a variety of ways, and with innumerable complications ; and we shall 

 no longer try to force the framework of a fish into a Procrustean bed, to which we 

 may reduce at the same time all other Vertebrates, with man. When the axis of 

 the body consists of a simple dorsal cord, we shall be willing to acknowledge that 

 it is not to be considered as an articulated back-bone ; when the skull-box con- 

 sists of a continuous cartilage, 1|}iat it is not to be artificially divided into isolated 

 parts; and, where there are no limbs at all, we shall not assume that they exist 

 potentially in the same degree of complication as in animals more favourably en- 

 dowed. And let it, not be supposed that such sobriety of views excludes general 

 comparisons ; it only withdraws them from the field of fancy to the rich field of 

 life." 



We must not stop now to suggest the explanation and defence with 

 which a disciple of Richard Owen might reply to this passage, but 

 the subject is certainly open to further discussion. The second chap- 

 ter is devoted to the families of Testudinata ; the third to the genera 

 and species, concluding with a view of the Chelonian faunse of North 

 America. The second volume is entirely devoted to the Embryology 

 of the order. We can hardly express too highly our estimate of the 

 value of this portion, which deserves the careful study of those who 

 desire really to understand this division of the animal kingdom, and 

 which displays an amount of exact knowledge, patient industry, and 

 minute research worthy of all praise. If these volumes, by the ex- 

 traordinary success of the subscription list, commemorate the great 



