522 



MR. H. N. RIDLEY ON THE 



Alpheus rostratipes, n. sp. 



Carapace smooth, anterior margin crescentically excavated, 

 the sides of the excavation being formed by the ocular hoods, 

 which are anteriorly produced but not furnished with spines, 

 and not separated from the rostrum by a depression. Kostrum 

 springing from the centre of the excavation, pointed, short, pro- 

 jecting slightly in front of the ocular hoods, but not reaching 

 the anterior margin of the first segment of the antennular 

 peduncle. Antennular spine reaching to the middle of the 

 second segment of peduncle. Segments of peduncle short, 

 approximately equal in length ; second segment furnished ex- 

 ternally with a small spine on its anterior margin. Antennal 

 scale as long as the antennular peduncle, much shorter than the 

 antennal peduncle. Basal segment of antenna furnished laterally 

 with a conspicuous spine. 



One of the legs of the first pair absent. The dactylus of the 

 remaining one (the smaller ?) closing vertically ; long, longer 

 than the manus, curved, pointed blade-like, when closed ; crossing 

 the thumb. Thumb almost as long as dactylus, and at the base 

 twice as thick, gradually tapering to a sharp, upturned point, 

 meeting manus at an obtuse angle. Manus elliptical, simple, 

 without constrictions or depressions, furnished close to the 

 dactylar joint -on each side with two blunt teeth, those on the 

 outer side being obscurely marked. Carpus furnished on its 

 inner side with a small blunt tooth. Meros three-sided, flattened 

 below, superior margin produced in front into a conspicuous 

 projection. Carpals of the second pair of legs becoming pro- 

 gressively shorter in the following order : — 1, 5, 2, 3, 4. 



Carpus and meros of third and. fourth pairs not furnished 

 below with a spine. Dactylus of fourth pair bifid, of third pair 

 absent. 



Alpheus, sp. 



(Too mutilated for identification.) 



Carapace furnished in front with a small pointed rostrum, 

 which projects slightly in front of the ocular hoods, but not 

 nearly to the anterior margin of the basal segment of the 

 peduncle of the antennula ; ocular hoods rounded and not spined. 

 Basal spine of antennula reaching to the anterior margin of the 

 basal peduncular segment. Second segment of peduncle longer 

 than the third, approximately equal to the first. Antennal scale 



