296 DISCOVERY REPORTS 



pede 3 with ischium and merus and basis fused; exopod with six setae, functional but 

 small. 



Legs 1-4 with large exopods, with 8, 8, 8, 6 setae. Leg i very large, with fully 

 developed chela. Legs 2-4 of simple larval type. Leg 5 a small bilobed rudiment. 

 Gills and pleopods absent. 



There can, I think, be little doubt that this larva belongs to the genus Nephrops or to 

 a closely allied genus. The precocious development of the chelae of leg i, combined 

 with the reduction of the exopods of maxillipedes i and 2, is unknown except in 

 Nephrops and Homarus. In Nephrops these exopods are much more reduced than they 

 are in Homariis, and they are remarkably like those of the larva here described. On the 

 other hand, the long rostrum, presence of three setae on the endopod of the antenna, 

 and the form of the telson are characters which would otherwise point clearly to the 

 Thalassinidea. The telson, indeed, is exactly the same as that of Callianassa and of 

 some larvae presumed to be Axiidae. This larva is a link between the Nephropsidae 

 and Axiidae, and points to the conclusion that the Nephropsid larva, which has been 

 so modified by shortening of development, has been derived from one of the Axiid- 

 Callianassid type. 



The possibility that this larva may belong to Nephropsis cannot be excluded ; but the 

 genus is apparently confined to deep water and its larva is unlikely to occur within the 

 Barrier Reef. 



Enoplometopus sp. (Figs. 3, 4) 



Discovery St. 690. 3° 17' S, 29° 57' W. Twelve specimens. 

 1580. 8° 44' S, 41° 50' E. One specimen. 



Smallest specimen : rostrum 5-6 mm. ; thorax and abdomen 1 1 mm. Largest specimen 

 about 24 mm. in total length. 



Rostrum much longer than antennule, broad and deeply hollowed at base, the raised 

 lateral margin bearing a few small teeth and continued, in larger specimens, backwards 

 as a ridge bearing three or four small teeth; anterior part laterally compressed, with 

 teeth on dorsal and ventral margins. Carapace, in the larger specimens, with faintly 

 marked cervical and branchiocardiac grooves and a well-marked ridge in posterior 

 region parallel to ventral margin ; no supra-orbital spines. 



Abdominal somites with dorsal ridge, and acutely pointed epimera on somites 2-5. 

 Telson narrow, parallel-sided, with a small spine at each posterior angle, between 

 which there is a triangular projection bearing a long median spine and seven or eight 

 setae on either side. No anal spine. 



Antennule without stylocerite; branches very long, the outer one very slender. 

 Antenna with large scale; basis with small outer spine. 



Mandibular palp of three segments ; incisor and molar parts not separated. Maxillule 

 without exite ; endopod slender, with three segments. Maxilla with small two-segmented 

 palp. 



Maxillipede i with endopod of two segments ; exopod widened at base, with a fringe 



