BihliograpMcal Notices. 169 



for the use of those who have arrived at some proficiency in the 

 study of geology. From its extreme comprehensiveness, there is 

 scarce!}^ a fact in general geology which is not alluded to in its pages ; 

 so that a studenjt who has once acquired a knowledge of the science 

 would be able, by a perusal of this little book, to refresh his me- 

 mory of what he has learned. Interleaved and furnished with a few 

 additional details and numerical data, it will form an admirable 

 pocket-companion for the young geologist in his excursions. 



The appendix contains, besides synopses of lectures, a valuable 

 table of the geological formations occurring iu the British Islands, 



A Manual of Zoology for the use of Students, ivith a general Intro- 

 duction on the Principles of Zoology. By Henry Alleyne Nichol- 

 son", M.D. &c. Small 8vo. Blackwood : Edinburgh and London, 

 1870. 



Advanced Text-Boole of Zoology, for the use of Schools. By H. Al- 

 leyne Nicholson, M.D, &c. Small 8vo. Blackwood : Edinburgh 

 and London, 1870. 



That there has long been a great want of a good manual of zoology 

 for tlie use of Students in this country there can be no doubt. Dr. 

 Nicholson must have felt this in his position as Lecturer on Natural 

 History in the Edinburgh Medical School ; and in the first work 

 indicated above he has endeavoured (not unsuccessfully) to supply 

 the deficiency. His treatment of the subject is evidently founded 

 chiefly upon Prof. Huxley's admirable ' Introduction to the Classi- 

 fication of Animals ;' and iu nearly all points which have been 

 specially touched upon by that great zoologist the author generally 

 follows him implicitly. Thus, as a matter of classification, Dr. 

 Nicholson accepts Huxley's subkingdom of Anuuloida in all its 

 details, although, in his introduction, he lays down the principle 

 that agreement in "morphological type" should constitute the 

 foundation of every group, and we should think it rather difficult 

 to demonstrate the existence of any unity of type in the groups re- 

 ferred to the Anuuloida. AYe cannot think that the presence in both 

 classes of a water-vascular system, and the agreement, such as it is, 

 in the mode of development of Nemertes among the Scolccida and 

 of the Echinodermata, can be held to furnish the necessary proof of 

 unity of morphological type ; and, on the other hand, if we were to 

 admit tliat Nemertes and the TurbcUaria (of which, however, Ne- 

 mertes is a very aberrant form) might form a subkingdom with the 

 Echinodermata, we should stiU be far from regarding the TurbcUaria, 

 Trematoda, Cestoda, Nematoda, Acanthocephala, Gordiacea, and 

 Rotifcra as constituting together only a single class. The fact is 

 that the class Seolecida, as thus constituted, is, like Cu\-ier's sub- 

 kingdom Eadiata, really the residuary dusthole for the reception of 

 every thing for which a suitable place cannot be found among the 

 well-defined primary groups of the animal kingdom ; and the 

 Echinodermata are unfortunate in being here again associated in a 

 Aan.i^ Mag. N. Hist. Her. 4. Vol.Vn. ' 12 



