DECAPODA. 
189 
Ranina, Lam., 
In which the elongated shell is gradually narrowed from before 
backwards, and usually resembles a reversed triangle with a den- 
tated base. The ocular pedicles are extended, and the lateral an- 
tennae long' and projecting. The external foot-jaws are similarly 
lengthened and narrow, and the extremity of the third joint is com- 
pressed into a point. All the feet are closely approximated, or 
almost contiguous at their origin, and from the fourth pair ascend 
towards the back; the two last, however, are alone on it. The for- 
ceps are compressed, have the figure of a reversed triangle, and are 
dentated ; the fingers are suddenly flexed. 
These Crustacea are closely allied to the Albunese of Fabricius, 
the first sub-genus of the following family, and thus form the passage 
from the Brachyura to the Macroura. From the approximation of 
the feet it is even probable that the genital orifices of the female are 
situated as in the IMacroura. According to Rumphius, they not 
only leave the water, but even climb to the tops of houses; from the 
form of their feet, however, this appears impossible, or at least very 
improbable. 
A fossil species was described by Aldrovandus, which the 
Abbe Ranzani and M. Desmarest have since made better 
known *. 
FAMILY II. 
MACROURA. — Exochnata, Fab. 
In the Decapoda Macroura, the end of the tail is provided with 
appendages! wl^ich most frequently form a fin on each side ; the tail 
itself is at least as long as the body, extended, exposed and simply 
* Ranina Ahlrovandi, Ranz., Mem. di Stor. Nat. ; Desmar., Hist. Nat. des 
Crust. Foss., VI, xi, 1. The fig. x, 5, 6, appears to us to belong to a Hippa 
rather than to a Ranina ; — Ranina serrafa, Lam. ; Cancer raninus, L; Alhunea scabra, 
Fal). ; Rumph., ISIus., VII, T. V. ; — Ranina dorsipes, Lam.; Allnmea dorsipes, Fab.; 
Rumph., Mus., X, 3; Desmar., Consider., XIX, 2. 
The genus Symethis, Fab., is unknown to us, but we presume it is allied to the 
Raminse, or the first subgenera of the subsequent family. 
'I- These appendages eonsist of three pieces, one of which serves as a base or 
pedicle to the others, and is articulated witli the penultimate segment; the latter, 
in conjunction with them, usually forms a fan-like fin; but in the last subgenera of 
this family these appendages are replaced by setaceous filaments. The false feet 
under the tail are similar in their structure to these natatory appendages. In the 
first subgenera they frequently do not exceed three or four pairs, and are smaller, 
or even null in the males, the two anterior ones always excepted ; the Pagura, as 
it appears to me, only have them on one side: the terminal pieces are often un- 
equal. In the succeeding ones, however, these feet are longer, and always form 
five pairs, the ova attached to them ; and they are used by the , animal in swimming. 
We observe that in the Macroura, where they are fewer in number, or less de- 
veloped as in those which we term the Anomala, the pednnede of the intermediate 
autenuK is longer in proportion than in the others, and that the two or four last 
four feet are smaller. These Crustacea, in some respects, seem also allied to the 
Brachyura. 
