2.98 PALvEMONID^, 



have very long filaments, which are marked with alternate 

 rings of dark and light colour through their whole length ; 

 the base cylindrical, and the scale diminishing in breadth 

 forwards, with a small tooth on the exterior margin at the 

 extremity. The internal antennae have but two filaments, 

 the external of which is the thicker ; the base is hollowed 

 to receive the eyes, and there is, at the anterior margin of 

 this excavation, a fringe of hairs, which covers the inferior 

 part of the eyes, and affords them protection. The ex- 

 ternal pedipalps have the basal joint hollowed above the 

 terminal joint, furnished with stiff hairs and small spines. 

 The anterior feet are simple, slightly curved, the basal 

 joint cylindrical, the remainder styliform, and acute at the 

 termination. The second pair of feet are of very unequal 

 length and size ; one being very slender, very long, the 

 wrist and arm multi-articulate, the didactyle hand very 

 minute ; the other thicker, shorter, likewise didactyle, and 

 with the arm and wrist multi-articulate ; the remaining 

 feet nearly of equal length, and simple ; the terminal joint 

 furnished with a row of spines beneath. The abdomen 

 resembles that of H'lppolyte in the gibbous form of the 

 third segment ; the centre piece of the tail has three pairs 

 of small teeth on its anterior half. 



The usual length is from two inches to two inches and 

 a half. 



It is of a reddish grey colour, curiously dotted and marked 

 with deeper red. 



At first sight this species may be readily mistaken for a 

 common prawn ; but a closer examination will shew that 

 its structural relations are much nearer to Hippolyte than 

 to Palcemon. Its distinction from the prawn appears to 

 have struck several persons about the same time. It 

 was first discovered, according to Dr. Leach, by the 



