Crangon and Galathea. 83 



carapace. Inferiorly, two triangular plates on each side probably represent re- 

 spectively the second antenual and sixth somites. 



The eighth and ninth somites have their appendages (the first and second 

 maxilhpeds) developed to a great extent as legs ; their chief office appears to 

 be to act as hands for the conveyance of the food to the maxillaj, and for the 

 guidance of the respiratory currents to the branchias. The second maxillipeds 

 are highly subpediform. 



The first chelipeds (tenth pair of limbs) are didactyle, the dactylos well 

 developed, hollowed like a spoon, and the opposing angle of the propodos, 

 produced, long and strong. 



The second to fourth chelipeds are well developed, nearly of equal size, 

 acuminate and simple. 



The fifth chelipeds (fourteenth pair) consist of the normal seven articula- 

 tions, but are developed as a pair of imperfect chelas; the basis, ischium, meros, 

 and carpus, slender ; the propodos slender, its distal angle developed as a tooth, 

 against which the dactylos is folded : this last is short, and not nailed, the 

 whole limb being carried folded up in the interspace between the carapace and 

 the fourth cheliped {vide infra). 



The eyes are moderate, and for the greater part of the length of their pe- 

 duncles concealed beneath the rostrum. In British species these bear a short, 

 haired scale on their summit. 



The olfactory autennse are moderate ; their peduncle is four-jointed, the 

 basal joint soldered to a narrow triangular plate, which fits in between the 

 mandibular segment and the branchial plate, which last, as already noted, pro- 

 bably belongs to the sixth somite. 



The auditory antennae are small, inserted on the membranous space beneath 

 the ocular peduncles, their somite appearing to be represented by a small 

 toothed triangular piece, which forms the external edge of the orbit ; their pe- 

 duncle is made up of four articulations, unless we look on the plate just spoken 

 of as the basal joint; the uppermost two of these are elongated and slender, 

 the basal short and robust. 



The filament is extremely short, multiarticulate, and bears at its origin a 

 curved multiarticulate appendage. 



The fourth pair (mandibles. Fig. X. 4) is six-jointed ; the coxae soldered 



