266 CRUSTACEA. 



by the muscles, and apparently acting in the manner of a cup or 

 sucker. Those of the second pair are prehensile, the thighs large and 

 spinous, and the tarsi composed of three joints, the last of which is 

 provided with two hooks. The remaining feet are terminated by a 

 fin formed of two elongated pinnulae, whose edges are fringed with 

 bearded threads : the two first of the latter, or those of the third pair, 

 including the four that precede them, have an additional but recurved 

 toe. The two last are annexed to that portion of the body which 

 projects posteriorly from the shell, or the tail. The female has but 

 a single oviduct, covered by two small feet situated behind the two 

 palettes. The organ which is considered as the penis of the male, 

 is placed at the internal extremity of the preceding joint of the same 

 feet near the origin of the two toes. On the same joint of the two 

 preceding feet, and facing these organs of copulation, is a vesicle 

 presumed to be seminal. The abdomen, by which we mean that part 

 of the body which extends posteriorly from the ainbulatory feet, the 

 rostrum, and a tubercle containing the heart, is entirely free, without 

 distinct articulations, and terminates directly after the last feet 

 behind, by a sort of tail, in the form of a rounded lamina, deeply 

 emarginated or bilobate, and without terminal hairs ; it is a species 

 of fin. The body is so transparent that the heart may be distinguished 

 through its parietes. It is situated behind the base of the siphon, 

 lodged in a solid tubercle, semi-diaphanous and composed of a single 

 ventricle. The blood, formed of little diaphanous globules, is 

 impelled forwards in a column which soon divides into four branches, 

 two of which proceed directly towards the eyes, and two towards the 

 antennae; the latter are then reflected backwards and united to the 

 former, constituting a single column on each side, which descends 

 towards the cup, turns round its base, and disappears. A little beneath 

 the two following feet, we may distinguish on each side another 

 sanguineous column which curves outwards, extends along the 

 borders of the shell, and having reached the two penultimate feet, is 

 flexed forwards and ceases to be visible. Another, where, as in the 

 preceding, the blood flows from the anterior part of the body to the 

 posterior, and traverses longitudinally the middle of the tail ; it unites 

 behind with two other currents that may be seen on the edges of the 

 tail, but which flow in a contrary direction, or appear to return the 

 blood to the heart, Jurine avoids using the term vessel, because the 

 blood which is driven into the anterior part of the body appears to 

 be diffused there in such a manner as to induce us to believe that its 

 globules, instead of being contained in particular vessels, are dispersed 

 in the parenchyma of those parts. From what we have stated, how- 

 ever, with respect to the circulation in the Dccapoda, it is evident, 

 that the blood, in the first instance, is distributed in the Arguli in the 

 same way, and that the currents or columns of which we have just 

 spoken seem to indicate the existence of peculiar vessels. This able 

 observer, in fact, subsequently acknowledges that the circulation is 

 not every where carried on in so diffused a manner as in the anterior 

 part of the shell, where, however, in our opinion, it is effectuated as 

 in the Decapoda. The brain, which is situated behind the eyes, 

 appeared to him to be divided into three equal lobes, one anterior and 



