186 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



3-5: distal segments slightly expanded, weakly spinose and plumose; 

 peraeopod 3 nearly equal in length to peraeopod 5. Coxal gills largest 

 posteriorly. Brood plates of gnathopod 2 small, narrow, vestigial on 

 peraeopod 3. 



Pleopods moderately strong, outer ramus 12-16 segmented, pedun- 

 cles short. Uropod 1 uniramous or with short inner ramus. Uropod 

 2 very small, single ramus spatulate. Uropod 3 stout, rami sub equal. 

 Telson small, subquadrate, entire. 



Type species. — Neohaustorius schmitzi, new species. 



Additional species. — Neohaustorius biarticulatus, new species. 



Remarks. — 'This genus is highly specialized for filter feeding but 

 peraeopods are relatively unspecialized for burrowing. The reduction 

 of uropods is the principal distinguishing feature of this genus. 



Neohaustorius biarticulatus, new species 



Figures Ij, 2e, 4z, 16, 17 



Material examined. — West Falmouth, Mass., Sippewisset Marsh, 

 Feb. 13, 1960, R. L. Wigley: 1 9, holotype (NMC 7028). Woods 

 Hole, Mass., east side of Nobska Point, fine sand at low water, 

 July 28, 1962, E. L. Mills: 1 9, ov., paratype (NMC 7029). 



Cape Cod, Mass., Little Sippewisset Marsh, sand bars near mouth, 

 midwater level, Sept. 8, 1963: 200+ subadult specimens; Great 

 Sippewisset Marsh, sand bars above mouth, midwater level, Sept. 8, 

 1963: 35 specimens (some ov. 99); Wild Harbor, sand bars near 

 mouth, midwater to low-water levels, Sept. 15, 1963; Herring Brook, 

 sand bars above mouth, midwater level, Sept. 19, 1963, R. L. Wigley: 

 10 specimens; Old Silver Beach, sand, low water, Feb. 13, 1960: 

 2 99; same locaHty, Jan. 30, 1960: 2 99 (MBL, author collections). 



Note: Two ovigerous females from Herring Brook lack any trace 

 of inner ramus on uropod 1, whereas a small inner ramus is present in 

 the other material. 



Description. — Female, 5.0 mm. Head very broad, margins sub- 

 parallel, rostrum short, anterolateral lobes sharply rounded, flaring 

 outwards. Eyes weakly pigmented. Peraeon lateral lobes well 

 developed. Antenna 1: peduncular segment 1 deep, lateral margin 

 with about 6 heavy plumose setae; segment 2 linear, anterior marginal 

 spines long, cleft tipped; segment 3 short; flagellum 6-segmented; 

 accessory flagellum, outer segment shorter than inner. Antenna 2: 

 posterior lobe of segment 4 deep, broadly arcuate, anterior margins 

 of 4 and 5 with row of simple, stiff setae; flagellum 4-segmented, 1st 

 shorter than 2 and 3 combined. 



Upper lip broadly rounded and apically smooth. Lower lip: outer 

 lobes with truncate inner margins, thickly pilose; inner lobes nearly 4 

 times as long as broad, lightly setose apically. Mandible: lacinia 



