C A RIDE A. 577 



Pacific, reef of Tongatabu. 



Length, seven lines. Colour, yellowish, with three brown longi- 

 tudinal bands in the abdomen, and two in thorax, the latter concave 

 towards one another. [Colours probably not constant for the species.] 

 The beak is curved slightly upward, and like the preceding is acute 

 at apex, both in a vertical and profile view. The larger part of the 

 first joint of the inner antennae is covered by the eyes. The eyes do not 

 project laterally beyond the carapax. The anterior angles of the cara- 

 pax are acute. The tooth at outer apex of second antennas projects 

 much beyond the terminal margin of the scale. The hand of the 

 second pair of legs is scarcely broader than the carpus, a slight pubes- 

 cence towards extremities of finger and thumb. The carpus is full 

 one-third as long as the hand. Six posterior legs hairy towards apex. 



GENUS ANCHISTIA (Dana). 



Pontoniee P&lsemonique affinis. Corpus vix depressum. Rostrum 

 tenue, scepius laminatum, elongatum. Oculi mediocres. Maxillipedes 

 externi omnino tenues. Antennce internee duobus flagellis instructce, 

 uno parce bifido. Mandibulfe non palpigerce. Manus secundce (in 

 speciebus scrutatis) sat gradles, elongates et cequales. Tarsi rectius- 

 culi tenues. 



Related both to Pontonia and Palcemon. Beak long, slender, usually 

 laminate. Eyes moderately large. Outer maxillipeds throughout 

 slender. Inner antennae furnished with two flagella, one sparingly 

 bifid. Mandible not palpigerous. Hands of second pair (in species 

 examined) rather slender, long, equal. Tarsi very slender and 

 nearly straight. 



The Auchistias form a link of relationship between Palasmon and 

 '(Edipus. Some of the species are precisely like Pala3mon> in form 

 and habit; yet the inner antennaa have properly but two flagella, 

 one of these two being bifid only for a very short distanc? at tip. 

 Moreover, the mandibles are without palpi. Unlike Harbilius and 

 CEdipus, the outer maxillipeds are slender throughout, a T d the tarsi 

 are nearly straight and slender, as in Palaemon. The aosence of a 

 palpus from the mandibles, is the surest characteristic for distinguish- 



145 



