April 2^, 1887] 



NA TURE 



603 



SPOLIA ATLANTICA 

 Spolia Atlantica. (i) Contributions to the Knowledge of 

 the Salpidae, by M. P. A. Traustedt ; (2) Remarks on 

 some of the Oceanic Annulata, by G. M. R. Levinsen ; 

 (3) Contributions towards the Morphology and Sys- 

 tematic Arrangement of the Pteropoda, by J. E. V. 

 Boas. (Copenhagen, 18S5-86.) 

 '"T'HE three monographs which at the instance, and 

 J- under the supervision, of the Directors of the Zoo- 

 logical Museum of Copenhagen, have been included in 

 one quarto volume under the title of " Spolia Atlantica," 

 originally appeared in the Transactions of the Danish 

 Royal Society of Natural Sciences. But although bound 

 together, each monograph in this I'ditioii dc luxe is com- 

 plete in itself, with separate title-page, table of contents, 

 descriptive plates, and all other necessary means of 

 separate reference, while the convenience of readers not 

 acquainted with Danish has been amply considered by 

 the addition of Latin and French translations of the de- 

 scriptions of the animals, and of many other important 

 parts of the text. 



The first of this triplet of monographs, which deals 

 with the so-called " aggregate " and " solitary " forms of 

 the several species of Salpre, is based on a study of the 

 exceptionally complete collections preserved in the Zoo- 

 logical Museum of Copenhagen, for which that institution 

 is mainly indebted to Prof Steenstrup, at whose sugges- 

 tion and under whose direction Herr Traustedt compiled 

 his memoir. The monograph presents a clear and com- 

 prehensive description of all the well-established species 

 of Salpae with their distinctive dual forms, and unqualified 

 praise may be given to the care with which the figures 

 have been drawn, and the admirable manner in which, 

 by means of pale blue outlines, the delicacy and trans- 

 parency of the bodies of the animals have been represented. 

 In treating of the Salpid;e, it is impossible to forget 

 how much of our knowledge of these curious animals is 

 due to the observations of Chamisso, the clever author of 

 " Peter Schlemihl,'' who, while serving as naturalist in the 

 exploring expedition of the Russian commander Kotzebue, 

 first discovered that the " aggregate " or chain Salpa 

 and the " solitary " Salpa were not distinct species, as 

 had been supposed, but only parts of the perfect or- 

 ganism of one species. By the discovery of this fact, 

 which Chamisso ingeniously, but, as subsequent in- 

 vestigations have shown, too fancifully, explained on 

 the hypothesis that these animals were subject to a law 

 of " alternation of generations," new and highly import- 

 ant paths of morphological inquiry were opened. Yet, 

 singularly enough, nearly thirty years passed after the 

 publication, in 1819, of Chamisso's treatise " De Animali- 

 bus quibusdam e Classe Vermium Linneana (de Salpis) " 

 before his observations were tested by further scientific 

 investigation. About the middle of the century Meyen 

 and Vogt turned their attention to the curious and 

 interesting phenomena connected with the embryonic 

 development of the Salpas. These inquiries were soon 

 followed by the still more important researches of Profs. 

 Krohn and Huxley, the latter of whom in a paper entitled 

 " Observations upon the Anatomy and Physiology of 

 Salpa and Pyrosoma," which appeared in the Phil. Trans. 

 i85i,has shown that Chamisso erred in his explanation 



of the nature of a " chain Salpa," which, to use Mr. 

 Huxley's words, " is nothing more homologically than a 

 highly individualised generative organ." 



Herr Traustedt does not enter into the question of the 

 embryonic development of the Salpidse, and hence his 

 work gives no information regarding the physiology of 

 these animals, nor does he in any way refer to the various 

 hypotheses that have been advanced in explanation of the 

 character of the " aggregate " and " solitary " forms. For 

 such information the student must go elsewhere. As a 

 guide to the anatomical structure of both forms in the 

 eleven species described and drawn by the author, the 

 memoir will, however, be found of great service, while it 

 contains much useful information as to the geographical 

 distribution of these animals not to be found elsewhere. 



In the treatise on "Some Oceanic Annulata" Herr 

 Levinsen supplies many interesting details regarding 

 various members of the families Alciopidae and Typhlo- 

 scolecidse, together with descriptions of several species 

 of Sagitta, to which are added lists of their geographical 

 distribution. In this, as in the memoir on the Pteropoda, 

 1 the illustrations are worthy of all praise. 



The memoir by Dr. Boas, which constitutes the last and 

 longest of the series, treats at great length of the mor- 

 phology, systematic arrangement, and geographical dis- 

 tribution of the Pteropoda. The materials employed by 

 the author were derived in part from the extensive col- 

 lections in the Zoological Museum of Copenhagen made 

 by, or under the direction of, Prof. Steenstrup, and in part 

 from numerous specimens placed at the writer's dis- 

 position by Profs. Dohrn, Mobius, Leche, and Spengel. 

 It is worthy of note that a very large proportion of the 

 specimens referred to as belonging to the Museum of 

 Copenhagen were obtained from amateur collectors ; 

 Danish naval officers, captains of merchant ships, and 

 travellers having responded with alacrity to Prof. Steen- 

 strup's appeal for help in obtaining samples of these and 

 other animals from remote regions. 



OUR BOOK SHELF 



Complete Hand-book on the Management of Accumulators. 

 By Sir David Salomons, Bart. Second Edition, revised 

 and enlarged. (London: Whittaker and Co., 1887.) 

 The author has for some years past had an installation 

 at his country residence for the purpose of lighting it and 

 for working motors which drive the machinery in his 

 large and well-equipped workshop. He has used accumu- 

 lators, as he informs us, ever since they may be said to 

 have been produced in commercial form in 1S82. No 

 expense nor trouble have been spared in making this 

 installation a model one, and experiments have been 

 made on many points in connexion with the subject. As 

 the whole installation has been made and worked under 

 his immediate personal superintendence, he has acquired 

 a considerable amount of experience, the result of which, 

 as far as it regards the management of accumulators, he 

 places before the public in this work. 



After a general description of cells of the E.P.S. and 

 Elwell- Parker type, he proceeds to give directions for 

 setting up and charging them. The causes of, and 

 remedies for, " buckhng " and " scaling " are discussed. 

 The harm caused by too rapid a discharge is pointed 

 out, and methods for preventing it are explained, as well 

 as various devices for regulating the E.M.F. of the charg- 

 ing current and that on the line. The method of cleaning 

 and " re-pasting " the plates is explained, and various 



