1252 



CRUSTACEA, 



Length of female observed, one-sixteenth of an inch ; of males, one- 

 seventh of an inch. Females, nearly colourless, not diaphanous. 

 Males, very brilliant with opaline reflections of various rich colours, 

 but mostly blue, and appearing like resplendent blue gems deep in 

 the water, flashing on the eye as they change their positions. 



The female has five joints to the cephalothorax, the first articula- 

 tion not very distinct ; the first segment is about as long as broad. 

 The second abdominal segment is the broadest. The caudal lamellae 

 have five setae, one at the inner apex quite short, the two apical 

 rather less than half the lamella in length ; the outer situated quite 

 near the base of the lamellae. The conspicilla are either on the front, or 

 mostly on the lower surface of the head ; they are much nearer to one 

 another than in the male, but are not in contact. Length of the 

 anterior antennae equalling about half the breadth of the cephalo- 

 thorax; setae more than half the length of the antennae. 



The male has nearly the same breadth anteriorly as the female. 

 The last or tenth segment is much narrower than the penult, and is 

 situated in the convexity of the penult, not projecting beyond it; the 

 articulation is not very distinct. Anterior antennae five-jointed. The 

 posterior antennae and caudal lamellae are as in the female. Stomach 

 small, somewhat triangular in form, the anterior angles being pro- 

 longed forward. 



Sapphirina gemma. 



Digitus antennarum posticarum articulo 2do parce brevior, tenuis, artv- 

 culls duobus digiti valde incequis, unguiculo brevi. Lamellce caudate 

 wbellipticce, latitudine duplo longwres, ad apicem internum minuti 

 aplculato, setis quatuor, brevlbus, duobus apicalibus, aliis externw. 

 Feminae: — Corpus gracillimum, elongatum. Cephalothorax b-articu- 

 latus articidatione prima fere obsolete segmento antko parce obhngo, 

 posticis inter sese similibus, sensim minoribus. Conspicilla remotius- 

 cula, inferlora, prope frontem inslta. Abdomen valde angustvus, 

 Q-articulatum,, segmentis primo secundoque subcequis, sequentibus vix 

 lunatls. Maris:— Corpus oblongo-subellipticum 10-articulaturn, seg- 

 mento antico paulo transverso, posticis latere non acutis. Conspicilla 

 remotiuscula, inferior a etfronte remota. 



Finger of posterior antennae slender, nearly as long as second jomt, 



