March 20, 1902] 



NA TURE 



459 



A STUD y IN FISH MORPHOLOG Y. . 

 Pleurojiectes. Liverpool Marine Biology Committers 

 Miinoirs on Typical British Marine Plants and 

 Animals. No. viii. By F. J. Cole and Jas. John- 

 stone, B.Sc. Pp. 252; II plates, 5 text figures and 

 a table. (London : Williams and Norgate, 1901.) 

 Price ~sy 



OF the now numerous publications of the Liverpool 

 Marine Biology Committee which have appeared 

 since its foundation, none are of greater service to zoo- 

 logists and students than those of the series to which the 

 volume under review belongs. They are each a detailed 

 study of some individual organism, prepared by a writer 

 or writers specially familiar with the group to which it 

 belongs ; and under this guarantee of authority, they are 

 consequently welcome and most useful wherever the 

 zoology of the British seas is studied or taught. The 

 first memoir, on the "Ascidian," by Prof. Herdman (to 

 whom honour is due for having inspired and initiated 

 this most admirable series), appeared but in 1899 ; and 

 in the interval of little more than two years which has 

 elapsed, there have been published seven others— the 

 present volume being the eighth. In bulk and descriptive 

 detail, this is by far the most extensive and elaborate yet 

 issued, since it is nearly three times the size of its 

 heaviest predecessor, and is illustrated by eleven plates 

 as compared with a previous maximum of seven. When, 

 however, it is remembered that it has two authors and 

 deals with a verteb rate, and that it exhausts not only the 

 organology, but treats of the life-history, habits and 

 economic aspects of the fish selected for treatment, it is 

 evident that a just allocation has been given it. Indeed, 

 in its method of treatment it is at once both wider and 

 more special than its predecessors. 



Both authors have already so distinguished themselves 

 as trustworthy investigators, at Liverpool and elsewhere, 

 that their cooperation gave promise of a good result, 

 and in the end our highest expectations have been 

 fulfilled. 



The introduction to the book opens with a con- 

 sideration of classification, the value of the Miillerian 

 subordinate term "anacanthini " (now unquestionably 

 doomed) and of the less familiar " heterosomata " being 

 duly explained. In dealing with the external characters, 

 the more recent work on chromatology is adequately in- 

 corporated, with due mention of authority ; and while 

 the descriptions of the lateral line organs and scales are 

 fully up to date, and the "breathing valves'' are duly 

 recognised, slight error is obvious only in the application 

 of the terms descriptive of the condition of the tail to 

 that organ and not the fish itself The subjects of torsion 

 and asymmetry, as involving the head and dorsal fin 

 and leading up to accurate definitions of the '"eyeless" 

 and "ocular" sides, are extremely well handled, both in this 

 introduction and in a subsequent section, following that 

 treating of the eye-muscles, which play so important a 

 part in the processes involved and in furnishing a clue to 

 their real nature. Rival theories are discussed, to the 

 denunciation of those of Cunningham, based upon the 



' Like three of its predecessors, which were written wholly or in part 

 by memhcrs of the staff of the Lancashire Sea Fisheries Laboratory, the 

 memoir is also incorporated as an Appendix in their Annual Report 

 Rep. X. iQot). 



NO. 1690, VOL. 65] 



study of the sole, certain other of whose observations 

 come in for criticism in many pages of this work. 



The osteological chapters come next in order of suc- 

 cession, and they are thoroughly good and sound. The 

 bones of the "eyeless" and "ocular" sides are alter- 

 nately described ; the compound nature of the pterotic 

 and sphenotic elements is fully considered, in its bearings 

 on both morphology and terminology ; the absence of 

 the left nasal is explained ; and the details in respect to 

 which the inter-maxillary cartilage enables the plaice (in 

 contradistinction to other Pleuronectid;c) to pick up food 

 on its eyeless side, are made admirably clear. The ver- 

 tebral column and fin-supports are fully considered ; 

 and while we doubt the advisability of retaining the 

 term " atlas " for the first vertebra, we welcome the 

 adoption of " axonost " and " baseost " and the recogni- 

 tion of the work of Traquair, Bridge, and others who are 

 named. We regret, however, that while our authors 

 were thus far revising their terminology they did not, for 

 once and for all, replace the term "anal" in ventral for 

 the post-anal median fin. 



Concerning the anal spine, it is noteworthy that the 

 authors have been at immense pains to be perfectly sure 

 that this does not project uncovered during life ; and it 

 may be said that no less labour has been bestowed upon 

 the accurate determination of the nature and precise 

 limitations of the pancreas, the lymphatic portion of the 

 head-kidney, the thymus gland, and other organs which 

 text-book writers are too apt to sketchily consider. Their 

 desire to be thorough at all costs is, in fact, one of the 

 distinguishing features of their book ; and consequently, 

 we find descriptions of the adult supplemented by com- 

 parison with the young, as in their account of the develop- 

 ment and retrogression of the thymus, of the thyroid 

 and suprarenal organs, of the hypoblastic origin of the 

 "bladder" (which we rejoice to find termed the 

 urocyst) and other allied parts. In all this and a great deal 

 more their memoir is a record of laborious research, done 

 for the love of the work and with the determination to be 

 exact ; and no less praiseworthy are their literary efforts, 

 which have led them, when called upon to deal with 

 things of doubtful homology or function, to state fully 

 alternative possibilities, with due reference to authority, 

 as, for example, in their treatment of the " interclavicle " 

 and the "pyloric ca;ca." 



The section dealing with the blood vascular system 

 calls for no especial comment, except that it is accurate 

 and well done, and that a good service has been rendered 

 in a rdsum^ a{ the chief conditions assumed by the pseudo- 

 branchial vessels. The authors' extreme caution is again 

 obvious, in their refusal to decide upon the homology of 

 this pseudobranch (in the absence of a related afferent 

 branch of the ventral aorta) until dealing with its in- 

 n rvation. And this leads naturally to the consideration 

 of their section on the nervous system, which, as might 

 be expected from the senior author's work, is their piece 

 dc resistance. In the portion of this which deals with the 

 cranial nerves, we are taken at once into a dissertation on 

 the two-root law of Bell and the four-root theory of 

 Gaskell ; and, apropos of the far-reaching investigations 

 of Strong and the labours of Herrick on Menidia, to a 

 classification, based on the " component theory " and work 

 done under the conviction that the whole course of these 



