442 



NATURE 



[September 7, 189; 



ition is greatly facilitated. As to nomenclature and 

 synonymy, Giesbrecht is very rigorous in favour of 

 priority, thus restoring even many older names to 

 species described by Claus. A complete list of all de- 

 scribed species, with complete indication of bibliography, 

 is to be found on pages 676-70J. The 54 plates contain 

 2300 figures, drawn masterly from nature by the author 

 himself, and the first five plates, as mentioned above, 

 give an idea of the variety of colour and form of append- 

 ages which exists even among these small marine 

 organisms. 



The systematical views and arrangements of Giesbrecht 

 differ considerably from those of former authors. It is 

 well known that the near relationship of the parasitical 

 with the free-living Copepoda has been recognised 

 already by H. Milne-Edwards ; but it was Zenker who 

 ■established systematically the two great groups of 

 Natantia or Gnithostomata, and Parasita or Siphono- 

 stomita, a division which hitherto has been universally 

 accepted. Giesbrecht points out the difficulties with which 

 this division meets when one considei-s natural affinities, 

 and thinks it impossible to adopt the manifold varieties 

 of the construction of the oral appendages as a funda- 

 mental basis for classification. He proposes to divide 

 the whole class into two great groups — the Gymnoplea 

 and the Podaplea. Tlie Gymnoplea are to be recognised 

 by the following characteristics: — (i) chief body division 

 occurring between the segment of the Jth foot-pair and the 

 genital segment ; (2) abdomen without rudiments of feet ; 

 {3) 5th foot-pair of the male transformed to an organ of 

 copulation, ge^iital organs asymmetrical ; (4) heart in 

 most cases present ; (5) female carrying rarely ovisacs ; 

 (6) extremities plentifully articulated and provided with 

 appendages. On the other hand, the Pleopoda are dis- 

 tinguished by (i) chief body division before the fifth pair 

 of feet ; (2) this latter rudimentary never serving as 

 copulation organ ; (3) male genital openings symmetrical ; 

 (4) heart always wanting ; (5) female carrying always one 

 or two ovisacs ; (6) extremities rather scarcely provided 

 with articulations and appendages. The great group of 

 the Gymnoplea is further divided into two trib5s — the 

 Amphaskandria (male with symmetrical antenns : family 

 Calanidre) and the Heterarthrandria (male on one side 

 with prehensile antenna : families Centropagida:;, Canda- 

 tida;, Pontellida:) ; to the family Centropagidae are to be 

 numbered all the Gymnoplea of fresh water. The 

 description of the group of the Podoplea only takes up a 

 small portion of the present monograph ; therefore our 

 author does not enter into a more detailed discussion of 

 its classification, especially as not only all the littoral 

 forms but most likely all the parasites belong to this 

 group ; he divides the group into two tribes — the Am- 

 pharthrandria (first pair of antenna of the male sym- 

 metrical prehensile organs : families Misophriidas, 

 MormonillidiE, Cyclopida;, Harpactitidse, Monstrillidoe) 

 and the Isokerandria (antennae of the male similar 

 to those of the female ; genital openings of the 

 female dorsally situated: families Ontasidae, Cory- 

 casidae). 



The rich harvest of pelagic Copepoda made by Capt. 

 Chierchia on the three years' expedition of the Italian 

 corvette, Vettor Pisani, enabled our author not only to 

 describe a great number of new or incompletely charac- 

 terised species of former authors, especially Dana's, but 

 it gave him the possibility of explaining his views on the 

 geographical distribution of the group, which we will only 

 sketch with a few words, since a larger discussion of 

 these views is impossible on account of the necessity to 

 enter on the general conditions of pelagic life. Accord- 

 ing to Dr. Giesbrecht there are three great districts in 

 the distribution of the pelagic Copepoda : two arctic ones, 

 north and south, whose boundaries are at 47° N. and 

 44' S., and the intermediate one. The number of species 

 belonging to this latter one is by far the greatest, almost 



NO. 1245, VOL. 48] 



85 per cent, of all known species, whilst the north Arctic 

 contains 5I per cent., the south Arctic i§ per cent. The 

 faunistic differences between these three districts are 

 greater than those of the three oceans ; nevertheless 

 there occur also in the Atlantic and in the Pacific species 

 peculiar to each of them, especially in their northern 

 parts. Pelagic Copepoda occur down to a depth of 

 4000 metres, and it seems that the boundaries of the 

 above-named three districts stretch even down to these 

 depths. Some species seem to live in very different 

 depths, others exclusively near the surface ; whether there 

 are such that live exclusively in greater depths has not 

 as yet been established. The character of the fauna de- 

 pending more on latitude than on longitude it seems the 

 determining causes of their geographical distribution 

 must depend chiefly on physical agents such as light and 

 temperature, but since the abyssal forms in the tropica! 

 parts of the Pacific ate not identical with those of the 

 northern and southern seas, which live on the same con- 

 ditions of light and temperature, the difference in the three 

 faunistic districts must be explained in part by still other 

 causes. The distribution of other holopelagic animals 

 seems to be identical with those of the Copepoda. Accord- 

 ing to Giesbrecht one seemsto be justified in attributin ^ the 

 causes of the daily vertical wandering of pelagic animals 

 to the influence of light, whilst the annual wanderings 

 depend on temperature ; besides these periodical wander- 

 ings some pelagic Copepoda seem to exist as eggs in 

 greater depths and go slowly to the surface after their 

 Nauplius stage. 



I refrain from entering here into any greater details of 

 the 831 large quarto pages of the volume lying before me, 

 expressing only the hope that Dr. Giesbrecht may soon be 

 able to publish his anatomical and embryological re- 

 searches on the same group in a second volume. But as 

 editor of the " Fauna and Flora," I may be permitted to 

 congratulate the Zoological Station and science in general 

 on the production of this volume, which answers fully to 

 the programme of the whole series of monographs. 



1 may be permitted to state here that another big 

 volume, treating of the Gammarida; of the Gulf of Naples, 

 and prepared by Prof Delia Valle, of the Universiiy of 

 Modena, will soon follow the Copepoda of Giesbrecht, 

 and will examine in a complete way these interesting 

 crustaceans, including their einbryology and anatomy. 

 Splendid plates accompany also the work of Delia Valle, 

 and will give perhaps for the first time the varied and 

 remarkable natural colouring of these creatures, generally 

 only figured in outline and diagram by former authors. 



After Delia Valle's monograph a large, highly inter- 

 esting, and most complete monograph of the Entero- 

 pneusta (Balanoglossus), by Prof Spengel (Giessen), will 

 be published. Most likely both these volumes will appear 

 this year. A very large work on the Cephalopods by 

 Dr. Tatta is in preparation, and its first volume, containing 

 the classification and grosser anatomy, accompanied by 

 most splendid plates, is nearly ready. A monograph by 

 Dr. Burger of Gottingen, treating the Nemerteans, is ready 

 in MSS., and the Ostracods, by Dr. W.' Miil'.er, of Greifs- 

 wald, are in the press ; the Hirudineaby Prof Apathy, of 

 Klausenburg, have been in hand for five years, a botanical 

 monograph treating the Rhodomelea;, by Prof Falcken- 

 burg, of Rostock, is nearj completion ; Prof. Ludwig will 

 contribute several volumes on iheEchinoderms, of which 

 most marvellous drawings by the artist of the Zoological 

 Station, Mr. Mercoliano, have been prepared, and several 

 other authors are engaged on other groups. 



Some years ago a discussion took place at the British As- 

 sociation, whether it would be right to continue the grant 

 for a table, and it was questioned whether the Zoological 

 Station at Naples was really destined for research and 

 not rather an educational institution ; if it were necessary 

 to strengthen the arguments in favour of the first state- 

 ment, I think the enumeration of the monographs of the 



