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Show 24 CRUSTACEA. are almost insensibly connected. They may all be united in single subgenus, that of PoRTUNus, Fab. Certain species( 1) peculiar to the Indian Ocean, such as the .lid. mete, Herbst., LVII, 1, are dist~nguishecl from all the following ones by their shell, which is of a transversely quadrilateral form, narrowed posteriorly, and whose ocular cavities occupy its anterior lateral angles; the eyes are thus separated by an interval almost equal to the greatest width of the shell. The insertion of the lateral antennre is at a considerable distance from these cavities. Other species, whose shell forms the segment of a circle, posteriorly truncated and widest in the middle, are remarkable for the length of their claws, which is at least double that of the shell. Each side pt·esents nine teeth, the, posterior largest and spiniform. The tail of the males is frequently very different from that of the females. These Portuni constitute the genus LuPA, Leach, and are mostly of a large size and foreign to Europe. One species, however, is found in the Mediterranean(2). A third division will consist of species analogous to the last in the form of their she11, but whose lateral teeth, usually :five in number, are nearly equal, or where, at least, the posterior tooth differs but slightly from the preceding ones; the length of the claws does not much exceed that of the shell. Those which have from six to nine teeth on each side are exotic. The Portunus tranquebaricus, Fabr., Herbst, Canc.r XXXVIII, 3, is the only one known that has nine equal teeth on each lateral edge; it is large, and is much esteemed as food. We suspect the P. leucodonte, Desmar., Hist. Nat. des Ct·ust. Foss., VI, 1-3, is the same species in a fossil state; it is also from India. The following species, all from Eut·opean seas(3), ha\1e five teeth on each lateral edge of the shell. (1) Genus TIIALAMITA, Lat. (2) Portunua Dufourii, Latr., Nouv. Diet. d'Hist. Nat., Ed. ll. This speciest figured in the Diet. Class. d'Hist. Nat., closely approaches the Cancer haatatua, Lin., which he says is found in the Adriatic. The following are to be referred to the same division: Cancer pelagicus, Herbst., lviii, 55,-C. forceps, Id., lv, 4; Leach, Zool. Miscell., liv;-C. sanguinolentus, Herbst., VIII, 56, 57;-C. cedonulli, Id., xxxix;-C. reticulatua, lb., 1;-C. haatatus, lb., lv, 1;-0. mene3tlw, lb., 3;- 0. ponticus, lb. 5. ( 3) For the Mediterranean species see Petagna, Risso and Olivi; fot· those on the western coast of France and the British seas, the Catalogue Methodique dell Cru&- 25 P. puber, Fab.; Cancer puber, L.; Penn. Brit. Zool., IV, ~v, 8; Herbst., VII, 59; Leach, Malac. Brit., VI. Covered w1th a yellowish down; eight small teeth between the eyes, the two middle ones longest, obtuse and divergent; claws sulcated, armed with a stout dentated tooth on the inner side of the carpus, and from one joint to the following one or the hand; finge~s blackis~. This species is usually called in France, where 1ts flesh 1s considered a delicacy, l' Etrille. P. corrugatus; Cancer corrugatus, Penn. Brit. Zool., IV, pl. v, 9; Leach, Malac. Brit., VII, I, ~· Th~ shell rugose, covered with a yellowish down, and furmshed wlth three equal, and almost lobuliform teeth in front; the three posterior teeth of the lateral margins very sharp and spiniform. P. mamas; Cancer mamas, L., and Fab. This c'ommon species of the French coast, called Crabe enrage, appears to me to belong to the Portuni, rather than to the Crabs properly so called; its posterior fins are only somewhat narrowe1·. Such '~as the first opinion of Dr Leach, who subsequently made a pecuhar genus for it called CAROINus, (Malac. Brit., XII, tab. v). It also has five teeth on each side, and a similar number in front, the internal oculars included. The top of the shell is glabrous, finely shagreened, with deeply impressed lines. The tarsi are striate; the uppe1· edge of the hand is so compressed as to form a rounded ridge terminated by a small tooth; a second but ' . stronger one is observed on the inner side of the. precedmg joint; fingers striate, and almost equally dentated, w1th a blackish tip. A fossil species is found in the marly limestone of MonteBolca, which, according to Desmarest,-Hist. Nat. des Crust. Foss., p. 125, is closely related to the mcenas. . In the Portunus Rondelet£i, Risso, there are no teeth m front. The one he calls longipes, presents the same character, but its feet are longer in proportion than those of other analogous species. We will form a fourth division with the subgenus. · PLATYONICHus, Lat. Which name has replaced that of Portumnus, Leach, on account tach du departement du Calvados," by llrebisson; and especially the excellent work of Dr Leach, MalacoatracCJ. Podophthalmia Britannim. M. Desma1'est has well developed the system of this author in his Conaideration8 Generales sur ZC3 ~rustaces, an extremely useful book to those who make this branch of Zoology the1r study. See also our article Portune, Encyc. Methodique. VoL. III.-D |
