REPORT ON THE AMPHIPODA. 153 



259 he quotes the observation that " tlie narwal is liable to the annoyance of a similar but 

 smaller animal," but remarks that Dewhurst must certainly be wrong in the opinion which 

 he expresses on the same page 259, that all species of whales are tormented by whale- 

 lice. 



1834. Milne-Edwards, Henri. 



Histoire naturelle des Crustac^s, comprenant ranatomie, la physiologie ct la 

 classification de ces animaux. Tome premier. Ouvrage accompagn^ de planches. 

 Paris, 1834. 



The Introduction, pages i.-xxxv. is chiefly occupied with an interesting sketch of the literature 

 of Carcinology down to the date of the work then in hand. The First Part, pages 1-200, 

 in the first chapter, discusses the position of Crustacea in the animal kingdom, the character 

 and various adaptations of the Crustacean integument, and its exuviation ; in the second 

 chapter, nutrition, respiration, circulation, and secretions ; in the third chapter, the organs 

 of sense, the nervous system and the muscles ; in the fourth, the apparatus of reproduction 

 and the process of development. In the Second Part, the first chapter, pages 201-236, 

 describes the different systems and methods employed up to that date in the classification 

 of Crustacea, concluding with that preferred by Milne-Edwards himself. 



Milne-Edwards considers the normal number of segments of the Crustacean body to be twenty- 

 one, the same segment never carrying more than one pair of limbs. Each segment he 

 composes theoretically of two arcs, an upper one constructed out of two tergal pieces with 

 an epimere or side-plate on either side, and a lower one constructed of two sternal pieces 

 with an episternum on either side. He says that M. Audouin has arrived at this general 

 principle, " que ce n'est que de Vaccroisseinent semhlahle ou dissemhlahle. des segmens, de la 

 reunion ou de la division des pieces qui les composent, du maximum de developpem,ent des uns, 

 de I'etat rudimen.taire des autres, que dependent toutes les differences qui se remarquent dans 

 la serie des animaux articulcs." After discussing the number of distinct segments in various 

 groups of Edriophthalma, he concludes by saying, p. 22, " Enfin nous ajouterons que dans 

 certaines espfeces d'Amphipodes les deux moiti^s lat(5rales du septifeme anneau abdominal 

 ne se r6unissent pas sur la ligne m6diane comme dans les autres segmens du corps, et qu'il 

 prends alors la forme de deux petites lames cornees ou de deux appendices styliformes, 

 disposition trfes-curieuse en ce qu'elle offre un exemple frappant de la division d'un anneau 

 en deux moiti^s sym6triques et laterales," with the following note, " Cela se voit dans la 

 Crevette d'Othon E., la Crevette locuste L, etc.; mais, dans la plupart des Amphipodes, ces 

 rudimens desseptiemes segmens abdominaux manquent complotement. {Voy. PL 1, fig. 5.)," 

 as though he thought that the presence of a telson in the Amphipoda was the exception, 

 whereas in the limits of this order which he accepted there is no instance of its absence 

 which can be regarded as certain. 



The appendages when fully developed, he says, present three distinct parts ; the main portion, 

 la tige, the stem which carries the other two and is almost always composed of several 

 joints placed end to end ; the second, or palp, is an appendage of the stem, on the outer 

 side of which it almost always takes its origin, generally from the basal joint, but sometimes 

 at the extremity of the second or third joint ; the thii'd portion, le fouet or flagellum, also 

 arises from the stem, separating from it always above and on the outer side of the palp, 

 p. 45. " In the natural group of the Amphipoda, the thoracic limbs almost always present 

 in the females the maximum of composition above-mentioned ; the stem serves for locomo- 

 tion ; the flageUum becomes membranous and serves for respiration j lastly, the palp takes 



(ZOOL. CHALL. EXP. — PART LXVII. — 1887.) XxX 20 



