258 ZOOLOGY. 



DECAPODA MACROLIRA. 

 PALiEMONIDjE ALPHEINiE. 



Genus RHYNCH0CINETE8, Edw. 



Gen. char. Body moderately compressed ; carapax exhibiting a spinous processus towards 

 the middle of the region of the stomach. Fronto-interocular margin provided with three 

 spines ; two more spines may he observed laterally upon the same anterior margin. Eostrum 

 very large, sword-shaped (ensiform) attached to the front b_y a gynglymic articulation in a ver- 

 tical plane, allowing a free motion downwards between the antennae, and upwards to a vertical 

 position of its axis. Its length equals^ or exceeds a little, that of the carapax. It is toothed, 

 or else denticulated upon its edges. Eyes conspicuous, and, when brought forward, find a rest- 

 ing place in an excavation of the peduncle of the superior antennfe, the basal article of which 

 is large, and armed exteriorly with a spiniform blade. The terminal tlireads of these append- 

 ages are two in number, and constructed as in Hippolyius. External jaw-legs pediform and 

 elongated ; their terminal article is slender, cylindrical, and spiny upon its apex. A rudimen- 

 tary palpiform appendage may be seen exteriorly at the base of each leg. Tarsus of second 

 pair of legs not multiarticulated. First pair of legs larger than the others, and stretching be- 

 yond the peduncle of external antennae ; pincers short and spoon-shaped ; finger moveable and 

 toothed. Second pair of legs very slender, terminated by a small chela, and shorter than the 

 third ; the tarsus of the latter and the following pairs being short and toothed as in Hijypoly- 

 tus. Abdomen not different from the latter-mentioned genus. Several pairs of small spines 

 upon the median blade between the caudal paddles. Gills, nine on either side of the thorax, 

 disposed ujjon a double row. 



Syn. Rliyiichochinetes, Edw. Ann. Sc. Nat. Deux Ser. Zool. VII, 1837, 165. — Hist. Nat. 

 Crust. II, 1837, 383. 

 Edw. et Luc. in D'Orh. Voy. Amer. Merid. VI, I, Crust. 1843, 35. 

 Nic. in Gay, Hist, de Chile, Zool. Ill, 1849, 215. 



Obs. There is one point in the history of this genus which cannot be looked upon with indif- 

 ference by naturalists — the fact that the only species on record, when first described, was given 

 for fatherland the Indian ocean. Specimens thus labelled had been deposited in the museum 

 of the Garden of Plants in Paris, and these became the originals from which Milne Edwards's 

 first description was drawn. As such it was produced in the Hlstoire naturelle des Crustaces. 



Subsequently, Alcide d'Orbigny brought to the same establishment specimens collected at 

 Valparaiso, which, on being submitted to Milne Edwards, were pronounced identical with those 

 previously described, and Valparaiso given as locality for the species, without any further 

 remark upon the subject. Nicolet, in Claude Gay's Historia de Chile, follows Milne Edwards's 

 determination ; adding, however, that the sole species hitherto known of this genus was indige- 

 nous both to the Indian ocean and to Chile. Dana, in his Report on the Crustacea of the United 

 States Exploring Expedition, adopts the views of his predecessors in regard to the identity of 

 the species, ascribing to it, in his tables of geographic distribution, a still wider range, since 

 it is stated to occur in the northern zone of the western coast of the Pacific ocean. 



The question now occurs as to whether the specimens labelled "Indian ocean," in the Paris 

 Museum, do really belong to that district, or else got a wrong label; no mention being made 

 by any one as to the channel through which they have been obtained. The figure published 



