ORDER PCECILOPODA. 
367 
have at their base a strong hook, toothless and recurved ; while 
the inferior are of four articulations, with a small tooth to the 
first. The siphon is directed forwards. The feet are twelve in 
number; the first two terminate by a basement, annulated 
transversely, widened circularly at the end, striated and den- 
ticulated on its edges, presenting at the interior a sort of 
rosette, formed by the muscles, and appearing to act in the 
manner of a cupping-glass, or sucker. Those of the follow- 
ing pair are adapted for prehension, with the thighs thick 
and spinous, and the tarsi composed of three articulations, 
the last of which is provided with two hooks. The other 
feet are terminated by a fin, formed of two fingers or 
elongated pinnulm, furnished on their edges with barbed 
filaments ; the first two of these, that is, the third pair, 
comprehending the two preceding pairs, have each an addi- 
tional finger, but recurved ; the last two are annexed to that 
portion of the body which projects posteriorly out of the testa, 
i. e. the tail. The females have but a single oviduct, and 
covered by two small feet, situated behind these two palettes ; 
the organ considered as the penis of the male, is placed at the 
internal extremity of the first articulation of the same feet, 
near the origin of the two digits. On the same articulation 
of the two preceding feet, and facing these copulative 
organs, is a vesicle presumed to be seminal. The abdomen, 
considering as such that part of the body which extends 
behind from the ambulatory feet, the beak, and a tubercle 
enclosing the heart, is entirely free, from its origin, without 
distinct articulations, and is terminated immediately after the 
last two feet, by a sort of tail, lamelliform, rounded, deeply 
emarginatcd, or bilobate, and without hairs at the end. It 
is a sort of fin. The transparence of the body allows the heart 
to be distinguished; it is situated behind the base of the siphon, 
lodged in a solid tubercle, semi-transparent, and formed of a 
single ventricle. The blood, composed of small transparent 
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