CEUSTACEA OP THE MEEGTJI AECHIPELAGO. 293 



the peduncle of the external antennae; the basipodites are 

 armed with an acute spine. The carpopodites of these legs 

 are scarcely twice as long as the hands, the fingers of which are 

 about as long as the palm. The third pair of legs, the last of 

 the chelate, are still longer than the two anterior pairs, for they 

 reach nearly to the distal ends of the penultimate joints of the 

 peduncles of the internal antennae, projectiug with the whole 

 hand beyond the peduncles of the outer antennae. The basi- 

 podites of the third legs are also armed with a slender, acute 

 spine, and their carpopodites are slightly longer than twice the 

 length of the hands, the fingers of which are almost as long as 

 the palm. 



As in other species of this remarkable genus, the legs of the 

 last two pairs present a different structure in the male and in the 

 female. The legs of the fourth pair of the male are much 

 shorter than those of the third pair, reaching only as far forwards 

 as the anterior legs. The basipodites are unarmed, and the 

 ischiopodites are as short as these joints ; the meropodites have 

 a characteristic form. These joints appear suddenly enlarged 

 at their under margins near the proximal fourth of their length, 

 and then again gradually'- taper towards their distal ends ; the 

 breadth of the enlarged part amounts to a fourth of the whole 

 length of the joint. The carpopodites, which are a little shorter 

 than the meropodites, present the usual slender form ; the 

 slender propodites are a little shorter than the carpopodites, 

 being slightly longer than half the length of the meropodites. 

 The straight, thin, and acute dactylopodites are only half as long 

 as the carpopodites. The legs of the fifth pair are a little 

 longer than the peduncles of the external antennae ; they are 

 unarmed at their bases, like the legs of the fourth pair. The 

 meropodites, which are slender and extend nearly as far 

 forwards as the hepatic spine of the cephalothorax, present a 

 peculiar notch or excavation near the proximal ends of their 

 under margins ; this notch is surmounted by a singular, subacute, 

 slightly curved, lamelliform prominence or tooth. A similar 

 structure has been described by Mr. Spence Bate as being 

 proper to the male of Penceus affvnis, M.-Edw. (Spence Bate, 

 " On the Penaeidae," ' Annals and Magazine of Natural History,' 

 1881, vol. viii. p. 179), and, according to him, this peculiar notch 

 is confined in that species to the ischium-joint of the fifth pair 

 of legs, whereas in this species the meropodites are marked with 



