1300 



CRUSTACEA. 



The second pair of antennae have the five short terminal joints to- 

 gether a little shorter than the preceding one ; and whole length of the 

 jive and the one preceding not one-fifth the length of the animal. The 

 large basal joint is longer than half the shell. The setae at apex are 

 about two-fifths the length of the animal. 



These two pairs of antennae and the spiculum, are usually protruded 

 through the front opening, as in fig. 6 a, and the posterior antennae 

 are the organs employed in the exceedingly rapid motions of the 

 animal. 



The mandibular feet are five-jointed, and the three terminal joints 

 are usually bent inward and backward, so that the organs lie like the 

 exterior maxillipeds of a Decapodous Crustacean. The second joint is 

 little more than half as long as base of second pair of antennae. The 

 first joint is placed transversely, and the adjoining parts of the two on 

 the inner side are prominent and corneous (brownish, or brownish-red), 

 so as to act together like a single mandible. 



First pair of maxillae lie obliquely just behind the base of the man- 

 dibular feet, and have short setae at apex. The whole of this organ 

 was not distinctly seen. 



A second pair of maxillae (or maxillipeds), has a large lamellar 

 plate ciliated with setae, attached to the base, and also a slender 

 appendage three-jointed, having a long seta at apex, which projects 

 backward. 



CONCHCECIA ROSTRATA. 



Agili similis; pedes mandibulares sensim non attenuati, articulis dwbus 

 apicalibus fere cequis, vix oblongis, setis longis; pedes penultirni duplo 

 longiores quam ultimi, et elongate setigeri. 



Near G. agilis; mandibular feet not becoming smaller to apex, the last 

 two joints nearly equal in diameter, scarcely oblong, setae long; 

 penult feet twice as long as the next following, having three long 

 setae at apex. 



Plate 91, fig. 7 a, posterior antennae; b, mandibular feet; c, max- 

 illa of first pair; d, second pair of maxillae; e, first pair of legs; f> 

 second pair of legs. 



