NO. 6.] ACCOUNT OF THE SPECIES. 55 



The anterior and posterior lips (PI. XII, figs. 8, 9) are of quite normal 

 structure. 



The mandibles (PI. XIII, fig. 2) have the masticatory part rather produced, 

 though only slightly expanded. Of the cutting teelh, the outer 2 are well 

 developed and bidentate at the tip, whereas the others are very feeble, seti- 

 form. The palp is shorter than the body of the mandible, and has the basal 

 part obliquely produced at the inner corner, so that the inner ramus projects 

 considerably beyond the outer, which is rather small. 



The maxillae (fig. 3) are distinguished by the strong development of the 

 masticatory lobe, which is unusually broad, and armed with about 12 strong, 

 denticulated spines. The vibratory plate, on the other hand, is poorly devel- 

 oped, and provided with only 6 comparatively small setae. On the terminal 

 part, or palp, the outermost lobe is likewise poorly developed, with only 2 

 apical setae. 



The anterior maxillipeds (fig. 4) are of moderate size, with the basal 

 joint more than twice as large as the others combined. The digitiform lobes 

 of the anterior edge are densely crowded together, and carry comparatively 

 short setae, the outermost of which assume a claw-like structure. The apical 

 setae issuing from the 2 outermost, very small joints, are short and simple, 

 being scarcely sensory in character. 



The posterior maxillipeds (fig. 5) are extremely slender and elongated, 

 with the 2nd basal joint very narrow and almost naked, forming with 

 the 1st a more or less abrupt, elbow-shaped bend. The terminal part is very 

 slender, almost as long as the 2nd basal joint, and is reflexed and provided 

 with only a very restricted number of setae. 



The natatory legs (figs. 69) are powerfully developed, and on the whole 

 built upon the same type as in the 3 preceding forms, though no trace is 

 found of the small spinules clothing the posterior face of the rami in these 

 forms. The inner ramus, however, in the 2nd pair (fig. 7), is uniarticulate, 

 like that in the 1st pair, and in the 2 posterior pairs it is only biarticulate; 

 but in all these pairs, on a closer examination, a slight indication of the for- 

 mation of a short 1st joint may be observed. In the 3 posterior pairs, the 

 outer ramus is very broad, with the apical spine strongly developed, and 

 bordered outside with a hyaline, serrated rim. 



