480 EXTRACTS FROM FOREIGN PERIODICALS. 



false legs, destined to carry the eggs, exist on the abdomen, and that these organs 

 are larger on one side than on the other. Lastly, according to Latreille, Bir- 

 gus has two rows of lamellar appendages under this part of the body. All these 

 opinions are more or less incorrect; In a great number of Paguri the abdomen 

 is covered above with transverse horny plates, considerably developed, and of a 

 sufficiently firm consistency ; and even when these plates are reduced to a rudi- 

 mentary state, they are almost always sufficiently distinct to mark the seven 

 rings of which this part of the body is composed. The two last rings are always 

 very firm, as are also the members of the penultimate segment, which serve to 

 retain the animal in its dwelling, and to carry the latter after it. The kind of 

 tail thus formed is always separated from the antepenultimate ring by a large 

 membrane ; in Birgus, as well as in the Paguri and the Cenobites, it exists, 

 and lacks all symmetry. The new genus which I have established under the 

 name Cancelle* is the only group of the tribe in which this terminal portion of 

 the abdomen is symmetrical. In the females we find, attached to the four 

 horned plates which represent the four abdominal rings comprised between the 

 first and sixth segments, four members which occupy the left side of the animal, 

 and which serve to bear the eggs ; these false legs are often large, and there 

 sometimes exists a similar one on the right side, but two rows are never found, 

 even in Birgus. In the male these organs are sometimes entirely wanting ; in 

 general there are three on the left side of the abdomen, and in certain Paguri it 

 exists on both sides. In these latter we find, immediately behind the posterior 

 thoracic legs, a pair of little appendages inserted near the median line, upon a 

 horny organ which represents the first ring of the abdomen; they are each 

 formed of a basilar articulation, and a terminal plate, shaped like a channel, 

 similar to what exists in the short-tailed decapods, and in many canceriform 

 Anomoures, forming my family Apterures. 



The horny plate which represents the second ring of the abdomen has also a 

 pair of symmetrical appendages, which are considerably more elongated, and 

 are inserted much further outwards, but which, in the ordinary position, are 

 bent forwards and inwards, so as to place itself between these with the first 

 pair. The three following segments each bear only one segment similar to those 

 of the second pair ; and it is to be observed, that in the Paguri, where the whole 

 number of these appendages only amounts to three, it is the last which exist, 



* While British naturalists in general attend little to vernacular nomenclature, continental 

 writers have, on the contrary, so great a regard for it as to give each genus a separate French or 

 German name, which they commonly employ without supplying the Latin designations. In the 

 case of new genera or species, this practice is certainly to be regretted ; and in France it is car- 

 ried so far as often greatly to embarrass the English student.— ?En. 



