1880.J NATURAL SCIENCES OF PHILADELPHIA. 219 



Genus CLISTOCCELOMA A. M.-Edwards, 1873. 



Cavapax sub-quadrate, sides dentate. Sub-ocular lobe large, 

 united to the front and excluding the antenna? from the orbit. 

 Meros of external maxillipeds short and rounded. 



C. balansae A. Milne-Edward?. 



Clistoca'lomn balanscv A. M.-Edw., Nouv. Arch, du Mus., ix, p. 311, 

 PI. XVII, f. 1 il873j. 



New Caledonia (A. M.-Edw.). 



Genus HELICE De Haan (1835). 



Carapax quadrate, front deflexed, sides straight, with one, two 

 or three teeth behind the orbital angle. Antennaj entering the 

 orbit. Meros of external maxillipeds as long as or longer than 

 the ischium, its external distal angle prominent, its distal border 



truncate. 



Synopsis of Species. 



Lateral margin with three teeth behind the angle of the orbit. 

 Ambulatory feet with a single distal spine on the meros. 



A transverse ridge on the branchial regions. tridens. 



No transveree crest on the branchial regions. 



Hands smooth. spinicarpa. 



Hands roughened. latreiUei. 



Meral joints of ambulatory feet with several spines. dentipes. 



Lateral margin two-toothed. 



Hand strongly granulate. gdiuUchaudi. 



Hand nearly smooth. 



Meral joints of ambulatory feet with a spine on the 

 upper distal margin, the hands of the male with a 

 pilose spot at the base of the fingers. pilimana. 



Meral joints without spines, hands of male without 

 pilose spots. crassa. 



Lateral margin one-toothed. gibba. 



Imperfectly characterized. leachii. 



H. tridens De Hnan. 



Helice tridens De Haan, op. cit., p. 57, PI. XI, f. 2, PI. XVI, f. 6 (1835). 

 Carapax longitudinall}- strongly convex, punctate, front curved 

 downward, its anterior border sinuate when vicAved from above. 

 Superior margin of the orbit sinuate, oblique ; lateral margin 

 with three teeth behind the orbital angle, the posterior tooth 

 rudimentary. Branchial regions with an oblique i-idge running 

 inward from this tooth. Orbits coarsel}' crenulate below. In- 

 ferior borders of the meral joints of the cheli]ieds with small 

 tubercles. Carpus spined on the inside. Hands externally 



