48G 
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 Cancelled 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 ia car¬ 
ried so far as often greatly to embarrass the English student.— Ed. 
