CRUSTACEA CASl'IA. 351 



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Remarks. — This species may be readily distiugiiislied from tlie 2 pre- 

 ceding ones by the very sleuder form of body, tlie comparatively small and 

 equal-sized antenuf^ the extremely feeble gnatliopoda, and especially by the 

 very much elongated last pair of uropoda, which latter characteristic has 

 given rise to the specific name. Only female specimens have hitherto come 

 under my inspection. 



Description of the female. 



Fully adult, ovigerous specimens scarcely exceed 6 mm. in length, and 

 accordingly, this species also belongs to the small-sized species of the genus. 



The form of the body (see fig. 17) is very slender and compressed, with 

 the back perfectly smooth throughout. 



The cephalon scarcely attains the length t)f the first 2 segments of meso- 

 some combined, and has the lateral lobes somewhat projecting and broadly 

 rounded at the tip, being defined behind by a rather deep emarginatiou. 



The anterior pairs of coxal plates are comparatively large and closely 

 contiguous, forming together on each side a perfectly continuous wall. Their 

 distal edge is only fringed with very small and scattered bristles. The 1st 

 l)'air (see fig. 19) are slightly expanded in their outer part, and obtusely 

 truncated at the tip; the 2 succeeding pairs are of a more regular, oblong 

 quadrangular form. The 4th pair (see fig. 21) are very large and greatly 

 expanded in their outer part, being fully as broad as they are deep, and 

 exhibiting an irregularly angular shape, with the posterior expansion verti- 

 cally truncated. 



The epimeral plates of the metasome are comparatively large, the last 

 2 being produced at the lateral corners to a somewhat obtuse point. 



The urosome is rather slender and perfectly smooth above, with only a 

 very small spiuule on each side of the dorsal face in the last segment. 



The eyes are of moderate size and oblong oval form, with well-developed 

 visual elements and dark pigment. 



The antennsB (see fig. 17) are unusually short and nearly equal-sized, 

 scarcely exceeding in length % of the body, and are supplied with scattered 

 fascicles of slender bristles. The superior ones (fig. 18) have the 1st joint of 

 the peduncle very large, being nearly twice as long as the other 2 combined. 

 The 3rd joint is rather short, scarcely longer than it is broad. The flagellum 

 is about the length of the peduncle, and composed of 6 articulations only. 

 The accessory appendage about equals in length the last 2 peduncular joints 

 combined, and is composed of 3 articulations. The inferior antennae nearly 

 agree in their structure with those in (t. minutus. 



The gnathopoda (figs. 19, 20) are extremely small and feeble, the post- 



^iis.-MuT. CTp. 331. y 



tj^i 



