1900.] FROil THE FALKLAND ISLANDS. 663 



In the discussion of tlie genus many of the distinctive 

 characters of this striking species have already been described. 

 Moreover, a very f uh and satisfactory account of it has been given 

 by Dr. Pfeffer, with a great number of excellent figures. In the 

 earlier representations both Dana and Cunningliam figure the fore 

 part of the pleon as a simple solid segment. This is the more to 

 be wondered at on Dana's part, as he, like Milne-Edwards, figures 

 the corresponding and similar portion of Amplioroidea typa with 

 all the requisite detail. 



The specimens brought by Mr. Vallentin from the Falklauds 

 are preserved in formol and are all of a semi-pellucid orange 

 colour, which under a lens shovvs a fine bordering to the seg- 

 ments and numerous dorsal markings of rather deeper tint, and is 

 closely speckled about the doj'so-latera! parts with minute greyish 

 points. 



It is only in large specimens that it is easy to make out the 

 sinuous suture which marks off the side-plates of the second to 

 the seventh segments of the perseon. The last of these segments 

 is scarcely so wide as the second segment of the pleon. 



In the fourth and filth pleopods both rami are respiratory, 

 consisting alike of plicated lamellae, as contrasted with the 

 (corresponding a])|)endages in some of the Sphaeromidse, in which 

 the outer ramus or exopod is opercular. Mr. Beddard. in the 

 'Challenger' Isopoda, p. 147, calls attention to "a similar hyper- 

 trophy of the respiratory lamellae '"' occurring in the two species of 

 Amplioroidea and in his own Cymodocea [Naesicopea^ ahyssorum. 



Two of Mr. Yallentin's specimens are of great size, the one 

 measured being 36 mm. in length by 23 mm. in breadth, agreeing 

 closely with the 3^ centimetres of Gruerin-Meneville's description. 

 With the large specimens were two others not more than 1 L or 12 

 mm. long, and one 23 mm. in length. 



Of his specimens Mr. Vallentin himself writes that the largest 

 " was found holding on to a large drifting piece of D'Urvillea 

 harveyi found in the harbour. The remainhig specimens 1 secured 

 on various occasions while collecting in my boat. During a calm 

 I frequently observed specimens of this species mount to the 

 surface of the sea, as if for a supplj^ of air, and immediately 

 return to the bottom. The depth of water where these Crustacea 

 were to be found was never less than two and half fathoms." 



Oniscoidea. 



1822. Oniscoidea, Sars, Christiania Vidensk. Forh. no. 18, p. 08. 



18S^»3. Oniseoidea, Stebbing, Hist. Crust., Internat. Sci. Ser. 

 vol. Ixxiv. p. 420. 



1898. Oniscoida, Sars, Crustacea of Norway, vol. ii. pt, 9, 

 p. 153. 



190(1. Oniscoidi'a, Jl. Eichards(in, The American Naturalist, 

 vol. xxxiv. p. 301. 



