BRACHYURA AND MACRURA 289 



Distribution. — Rio Janeiro? (Dana) ; Cape Verde Islands (A. 

 Milne Edwards). 



Synalpheus neptunus (Dana). 



Alpheus neptunus Dana, Crust. U. S. Expl. Exped., i, 553, 1852 ; pi. xxxv, 



f. 5. 1855. 

 Synalpheus neptunus Covrit^^., Ann. Sci. Nat. (8), Zool., ix, 15, 1899. 



Two specimens were taken at Tagus Cove, Albemarle Island, on 

 the reef north of Tagus Hill. In these specimens the rostral spine is 

 longer than the orbital, but still not reaching the end of the first anten- 

 nular segment. The antennular scale reaches one half the length of 

 the second antennular segment. The blade of the antennal scale 

 reaches just beyond the middle of the third antennular segment ; the 

 spine of the scale scarcely reaches the end of the antennular peduncle. 

 The basal spine of the antenna exceeds the first antennular segment a 

 little. The antennal peduncle is longer than the antennular. 



Distribution. — Sulu Sea, 6^ and 9 fathoms, and Fiji Islands 

 (Dana); Red Sea (Heller, Paulson); Bermudas; Porto Rico, 10 

 fathoms. 



Family DISCID^ fam. nov. 



Monocarpinea in which the animal is smoothly rounded, not cari- 



nated ; the rostrum short, depressed ; the antennules biflagellate, the 



outer flagellum with a thickened basal portion ; 



the antennal scale short and broad ; the mandible 



furnished with a molar process and palp ; the 



external maxillipeds provided with an exognath ; 



all the pereiopods with exopods ; first pair of 



pereiopods much larger than the second ; both 



pairs with extremity of merus cup-shaped and 



articulating at its lower angle only, with the ^^^- '• ^'^'^'^^ 

 1,1^, e n ^ • • serrifer, mandible, 



carpus ; carpus short ; dactylus of first pair cir- f . 



^ ^ •' ^ , much enlarged. 



cular ; pollex slender ; fingers of second pair nor- 

 mal ; feet of last three pairs diminishing regularly in length, and 

 having dactyli spinulous beneath. 



This family is allied to the Atyidae and the Oplophoridae (= Acan- 

 thephyridae). The Atyidae inhabit fresh water; they have the first 

 two pairs of pereiopods similar, with spoon-shaped fingers, and the 

 mandible without a palp. In the Oplophoridae the animal is dorsally 

 carinated, the antennal scale is long and rigid, the first two pairs of 

 pereiopods are long, slender and similar. 



