Bibliographical Notices. 169 



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

 study of geology. From its extreme comprehensiveness, there is 

 scarcely a fact in general geology which is not alluded to in its pages ; 

 so that a student 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 numeiical data, it will form an admirable 

 pocket-companion for the young geologist in his excursions. 



The ajipendix contains, besides synopses of lectures, a valuable 

 table of the geological formations occurring in the British Islands. 



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

 duction on the Pi'inciples of Zoology. ByllEXRY Alleyxe Xichol- 

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

 1870. 



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

 LETNE NicHOLSox, M.D. &e. Small Svo. Blackwood : Edinburgh 

 and London, 1870. 



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

 for the use of Students in this countiy there can be no doubt. Dr. 

 Nicholson must have felt this in his position as Lecturer on I^atural 

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

 indicated above he has endeavoured (not unsuccessfully) to supply 

 the deficiency. His treatment of the subject is evidently founded 

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

 fication of Animals ;' and in 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. 

 Xicholson accepts Huxley's subkingdom of Annuloida in all its 

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

 that agreement in "morphological type" should constitute the 

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

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

 ferred to the Annuloida. "We 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 Scolecida 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 that Nemertes and the Tiirbellaria (of which, however, Ne- 

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

 Echinodermata, we should still be far from regarding the Turbellaria, 

 Trematoda, Cestoda, jS'ematoda, Acauthocephala, Gordiacea, and 

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

 that the class Scolecida, as thus constituted, is, like Ciivier's sub- 

 kingdom Radiata, 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 

 Ann. (.{:Marj.N. Hist. Scr. 4. VolVii. 12 



