ggg CRUSTACEA. 



with which it was found; a, the animal, enlarged; b, upper view of 

 head and eye ; c, basal portions of antennas ; d, terminal stylets ; e, 

 one of the first pair of stylets. 



Length, one-sixth of an inch. Colour, more or less entirely ultra- 

 marine. The body is more slender than in the idtramarina above 

 described, and has no convexity along the back, the dorsal line of 

 thorax, as seen in profile, being straight, or even concave. The exca- 

 vation in the lower part of the head, from which the antennas proceed, 

 is very large, being as broad as the part of the head immediately 

 above. The thorax consists of seven segments, of which the first is 

 shortest. The epimerals were not distinguished. The superior an- 

 tennas are sparingly shorter than the inferior ; the inferior but little 

 shorter than the body; nagellum of the inferior pair scabrous. 

 The blue colour was deepest along the venter. The four anterior legs, 

 and the base of the superior antennas, had the same rich blue colour. 



Under the idea that this was a distinct species (which it may still 

 be), I had named it Synopia gracilis in my original manuscript. 



Synopia angustifrons. 



S. ultramarinas similis. Caput angustius, ejus lateribus inter sese 40°- 

 45° divaricatis. Antenna? 2dce corpore breviores, flagello 10-articidato, 

 articulis tenuibus, cylindricis; Imce basi inferiorum paululo longiores, 

 flagello h-articulato. Paris quarti manus ad dorsum recta, infra ar- 

 cuata; digito tenui, articulis duobus subcequis. 



Similar to the S. ultramarina. Head much narrower, the sides of the 

 same converging forward at an angle of 40° to 45°. Inferior an- 

 tennas considerably shorter than the body, nagellum 10-jomted, 

 joints slender, cylindrical; superior pair but a little longer than 

 base of inferior, nagellum five-jointed. Hand of fourth pair straight 

 along the back, and arcuate on the opposite margin, finger slender, 

 consisting of two nearly equal joints. 



Plate 68, fig. 8 a, animal, enlarged; b, upper view of head; c, supe- 

 rior antennas ; d, second pair of legs. 



