^909 Reviews. 181 



REVIEWS. 



LAMPREYS AND FISHES. 



A Treatise on Zoology. FMited by Sir Ray IvANKRSter, K.C.B., 

 LL.D., F.R.S. Part IX. Vertebrata Craniata, first fascicle 

 Cyclostomes and Fishes. By K. S. Goodrich, ^r.A., F.R.vS. 



London : A. &• C. Black, 1909. Pp. xvi. + 518. Price 15s. net. 



lu passing some adverse criticisms on the inadequate treatment of the 

 mode of life and distribution of animals in previous volumes of this 

 treatise, we were unaware that this great work was intended to comple- 

 ment the well-known Cambridge Natural History. In a note printed in 

 last month's Irish N'aturalist (July, J909), Dr. Bather gives us to under- 

 stand that the scope of the treatise is limited to "systematic zoologv on 

 modern lines.' His statement that this was clearly indicated in the 

 prospectus cannot be easily verified by the student who would naturall}- 

 turn to the first volume for such an explanation. 



A discussion of " facts that have no obvious bearing on taxonomy " 

 would no doubt have made the treatise somewhat unwieldl}', but we are 

 of opinion that it would have been desirable to include certain features 

 in the direction indicated that certainly have a bearing on taxonomy. 



Ten pages of Mr. Goodrich's volume on Cyclostomes and Fishes (pp. 

 73-82) are devoted to a description of the origin of paired fins. Few 

 zoologists probably are more competent than he is to give us such a brief 

 and yet masterly exposition of the complex problems connected with 

 this subject. The identification and enumeration of the segments of 

 which the head of a vertebrate is composed constitutes another and 

 possibh' still more intricate topic. For it is now recognised that the re- 

 mote ancestor of those vertebrates (craniata), which possess a skull, must 

 have been segmented right to its anterior extremity. The great difference 

 in structure between head and trunk is probably due to divergent 

 specialisation of two regions of the bod}- which primitively resembled 

 each other. Mr. Goodrich supplies a careful description q>{ the nervous 

 system and sense organs, the mesoblastic somites, and the gill arches and 

 slits, which are the three chief sets of structures to be studied in connec- 

 tion with this identification of the head-segments. Thus the early history 

 of the skull is gradually being elucidated. Much more work, however, is 

 needed in this direction. Two papers — one by H. E. Ziegler^ the other 

 by P. Brohmer^ — on the origin of the head of vertebrates, have been 

 published since Mr. Goodrich's volume went to press, and have thrown 

 fresh light on some obscure points. 



Lampreys and Hagfishes have for some time been entirely separated 

 from the class Pisces. They can no longer be looked upon as true fishes 

 since they differ from the latter in many salient structural characters. The 

 strongest evidence of their primitive position is to be found in the larva 

 of the Lamprey, which has certain features of resemblance with the 



^ Zeils. f. Natwwissensch., xliii., 1909. "^ Jb.., xliv., 1909. 



