534 



NATURE 



[July 24, 191, 



The systematic part of the work contains a most 

 useful revision of the known species of Chato- 

 gnatha with a detailed key giving- brief diagnoses 

 of the genera and species, as well as a fuller state- 

 ment of characters, with measurements of many 

 specimens in the case of most species. 



In the very full discussion of the problems of 

 distribution, illustrated by many tables, we find 

 that our author considers that his data contain 

 numerous examples illustrating lack of uniformity 

 in distribution. Some of these examples are as 

 follows : In two hauls of the same net in the 

 same region on the same day the number of 

 Sagitta bipunctata varied from fifteen at 6.20 a.m. 

 to one at 7.20 a.m. per unit volume of water. On 

 another day, under similar conditions, the number 

 varied from twenty-five to one, and on another day 

 similarly from one to fifty-six, and on still another 

 occasion from 135 to one. " Other instances might 

 be cited, but enough have been given to show that 

 the surface-distribution of 5. bipunctata is not 

 constant for any length of time, even in very small 

 areas._ The objection will be made that 'hydro- 

 graphic and meteorological conditions change 

 rapidly near the coast, but remain constant on 

 the high seas. I doubt the validity of such an 

 objection. In the first place, owing to variations 

 in wind, rain, light, barometric pressure, heat, 

 &c, it is very improbable that hydrographic and 

 meteorological conditions even approach constancy 

 on the high seas. In the second place, some of 

 the above examples show that S. bipunctata 

 varied in abundance even when these conditions, 

 so far as known, remained constant during the 

 period within which the contrasted hauls were 

 made." 

 _ The author finds himself in agreement with 

 similar observations that have been taken in recent 

 years in the Irish Sea, and comes to the con- 

 clusion that "we are therefore compelled to ac- 

 knowlege a very definite causal relation between 

 rate of reproduction and variations in the quantity 

 of plankton. " He discusses the influence of other 

 organisms on the abundance of plankton, and 

 illustrates it by the effect of "red-water," due to the 

 presence of enormous numbers of the dinoflagell.it e 

 Gonvaulax, and recognises, consequently, that to 

 estimate adequately the quantity of plankton in 

 a given.area of the sea we must consider far more 

 than the physical and chemical conditions, and 

 must not omit the biological influences involving 

 the effects of growth, reproduction, food-relations^ 

 and other activities of the organisms concerned.' 

 As Kofoid (1903) has demonstrated, there are 

 variations in the quantity of plankton which are 

 nearly, if not entirely, independent of hydrographic 

 and meteorological conditions. 



Mr. Michael shows that Sagitta bipunctata. the 

 commonest species that he deals with, is "epi- 

 planktonic," and, moreover, migrates towards the 

 surface at night and into deeper zones in the day. 

 In the surface-nets this species attains its morning 

 maximum within an hour after sunrise, and its 

 evening maximum within an hour after sunset. 

 He considers that it is probable that the species in 

 NO. 2282, VOL. 91"] 



its diurnal migrations is constantly movir.g towards 

 that zone of water in which "twilight conditions " 

 are to be found. The effects of salinity and tem- 

 perature are also investigated in detail, and the 

 conclusion that our author arrives at is that "pro- 

 bably light has more pronounced effect on vertical 

 distribution than temperature or salinity, because 

 its variations are more regular and periodic." 



It is interesting to find that in a later paper in 

 the same series from the University of California, 

 viz., C. O. Esterly on the distribution of the 

 Copepoda of the San Diego region, precisely the 

 same general conclusions as to irregularity of 

 distribution of the plankton are arrived at. In 

 speaking of the absence of any uniformity, the 

 author of this later paper says : " Instances of 

 this could be given almost without number in 

 regard to the distribution of the Copepoda of 

 this region." The marine biologists of the Cali- 

 fornian coast are clearly to be congratulated on 

 the thoroughness with which their investigations 

 are being carried out, and on the sound con- 

 clusions at which they are arriving. W. A. H. 



PROF. FRANCIS GOTCH, F.R.S. 

 TTHE phenomena of life and their cessation at 

 A death present varied interests attracting to 

 their investigation minds of very diverse type. 

 Thus when the foremost ranks of physiology show 

 a new-made gap, and a distinguished service of 

 some one particular kind is at an end for ever, 

 the loss to the science is not readily repaired. It 

 is then too clear that the gifts which have 

 vanished have differed from those that are left 

 more than in degrees of excellence. Thus deeply 

 at the present time physiology suffers by the death 

 of the late Prof. Francis Gotch. His name is 

 significant of a world-wide reputation. His per- 

 sonality was obviously individual, and in its pecu- 

 liarities excellent. 



Nothing that can be said in the near future can 

 add to or detract from his established reputation. 

 A master of the technique in one particular line, 

 his measurements stand until that technique under- 

 goes unforeseen developments and improvements. 

 In that branch of the subject which he had made 

 his own he had contributed to knowledge a long 

 series of very precise data, placed with o-reat skill 

 at points of salient interest. Feeling no need for 

 the incentives provided by explanatory hypotheses, 

 testing no particular form of speculation, he has 

 patiently and with great ingenuitv assisted in a 

 fundamentally essential survey of the physical 

 evidences of life as studied in nerve, muscle, the 

 retina, the special organs of electrical fishes, and 

 in the central nervous system. Further than this, 

 he was a distinguished authority upon the litera- 

 ture of this subject, and a writer of valued sum- 

 maries and lucid historical articles. 



Judged from his writings, he was what I have 

 thus too briefly stated, namely, a dispassionate 

 contributor, and a cold analyst, of evidence. 

 Mrange as may seem the contrast, to his students 

 he was a magician, a marvellous weaver of deft 



