1899] A PICTURE-GALLERY OF THE ISO POD A 293 



But since the time of Latreille there have been discovered in the depths of the 

 sea and elsewhere, numerous species of Isopoda, in which the inequality and 

 dissimilarity of the legs attached to one and the same body is carried to an 

 almost extravagant extent. This will be seen at a glance by any one who only 

 turns over the excellent plates with which Sars's work is illustrated throughout. 

 The plates of the present volume are 104 in number. They would often be 

 a kind of revelation to the casual observer, who seeing sees not, as he gazes 

 at the animals themselves in the specimen glasses of a museum. The student 

 also, preparing to dissect a rare isopod, should certainly first make himself 

 acquainted with these drawings before attempting the severance of minute and 

 delicate organs, which may be rendered undecipherable by one rash thrust of 

 an ignorant needle. 



As regards classification, it may be remarked that Professor Sars retains the 

 Tanaidae among the Isopoda. This has the great merit of present convenience, 

 whether or not at some future date the separatist party may succeed in detach- 

 ing this group from its near allies. Most of the species of it, according to 

 Sars, construct for themselves abodes of mud, into which they may wholly 

 withdraw their bodies. On the English coast, however, there is one species 

 pretty frequently to be found, along with the Gribble, in the honeycombing of 

 submerged timber. On the group at large the Professor makes another observa- 

 tion, which is of much interest to the collector. " They all, moreover," he 

 says, " exhibit this peculiarity, namely, that in reaching the surface of the 

 water they remain floating, without being able to re-immerge their bodies, 

 whereby the discovery of the generally very small and inconspicuous specimens 

 is essentially facilitated. On placing some muddy clay taken from greater 

 depths, in a shallow vessel, and stirring up the mud, they will very soon appear 

 floating on the surface, like small white pins, and may easily be taken up for 

 a closer examination." Naturally this mode of discovery will apply to the 

 tenants of mud from small depths as well as great, and in some localities to 

 the sand-dwellers of the sea-shore. 



To the elucidation of the tribe Epicarida, it will be found that the work 

 under review has made a very valuable contribution. In this tribe not Alps on 

 Alps, but shrimps on shrimps arise. The Isopoda of which it is formed, in all 

 sorts of insinuating ways, implant and engraft themselves upon other crustaceans, 

 in the process assuming oddities of form, distortions and degradations, in 

 pleasing but often extremely puzzling variety. There is plenty of work 

 apparently still to be done in this branch of investigation, but the intricacies 

 of it have been wonderfully disentangled by the labours, whether in conflict or 

 agreement, of Giard and Bonnier, of Kossmann and of Sars. 



In the great variety of species, normal and abnormal, which are shown to 

 belong to the isopod fauna of Norway, it is singular that the Sphaeromidae 

 find no mention. This is a family of extremely extensive distribution in the 

 sea, and is represented even in fresh water. To one of the species incidental 

 allusion was made at the beginning of this notice, simply because it is among 

 the most familiar of British marine Isopoda, so that the absence of the whole 

 family from Norwegian coasts and waters may well cause surprise. 



The volume just completed is published by the authorities of the Bergen 

 Museum. To them, therefore, as well as to the author, science is much indebted. 

 There is one small but not unimportant improvement by which they might 

 easily increase the obligation. The seven double parts of the original issue 

 bear dates extending over four years, from 1896 to 1899. When the wrappers, 

 which are of an essentially unstable character, are removed, the bound volume 

 will contain the latter date alone. Since it teems from one end to the other 

 with original observations, and with definitions and descriptions of new genera 

 and species, the reader ought surely to be supplied with some means of ascer- 

 taining the true dates of its several parts. This could have been best effected 

 by printing month and year of issue at the foot of the last page of the text, 



