634 CRUSTACEA. 



Erichthina demissa. 



Carapax latus, latitudine pairto longior, postici paulo angustior, rostro 

 longo et crasso, deorsum valde inflexo, nudo, margine carapacis postico 

 dnuoso, medium spina brevi acuto, angidis posticis breviter acutis, mar- 

 gine antero-laterali rotundato, non acuta, laterali Integra. 



Carapax broad, a little oblong, a little narrower behind, beak long and 

 stout, flexed very much downwards, naked, posterior margin of 

 carapax sinuous, at middle acute with a short spine, posterior angles 

 short acute, anterolateral margin rounded, not acute, lateral mar- 

 gin entire. 



Plate 42, fig. 3 a, b, c, different views, enlarged ; d, still younger 

 individual of the same. 



Near eastern entrance of Straits of Sunda. Collected, March 3, 



Length of individual represented in figures a, b, c, about one-six- 

 teenth of an inch; of that of fig. d, one-twenty-fourth of an inch. 

 The legs are only partly developed, and none are cheliform. The first 

 antennas in the largest specimens, simple, consisting of a short basal 

 joint, a second joint rather long, and three short apical ending in a 

 few sete. The second pair are two-branched, one branch multiarti- 

 culate and setigerous, the other two-jointed. The leo-s of the last 

 thoracic segment were not at all developed, of the five pairs next pre- 

 ceding rudimentary, the posterior largest; two preceding pairs bifid 

 andsubnatatory; the branches two-jointed and furnished with a few 

 sete. Preceding these, two pairs appear to correspond to maxilte 

 and maxilhpeds. The eyes were large and compound, but were 

 wholly covered by the shell. The abdomen was long linear seven- 

 jointed, the sixth a little longer than preceding, the seventh twice as 

 long as sixth and short bilobate behind, with a number of divergent 

 sete on the margin. Caudal appendages about as long as caudal 

 segment. 



In the younger state (fig. 3 c), the segments of the abdomen were 

 distinctly separated; there were no compound eyes and only a minute 



