558 PROCEEDINGS OF THE NATIONAL MUSEUM vol.84 



conspicuous median noselike process. The nasiform process and 

 the expanded corners of the labrum are covered Avith stiff bristlelike 

 hairs grouped in small oblong patches and comblike rows. 



The mandible has a large heavy tooth at the posterior angle of 

 the triturating surface. On the dorsal border of this surface 

 the large tooth is followed by a wide gap, then by three or four 

 heavy teeth, which diminish in size. The anterior and ventral borders 

 are bordered by numerous small, needlelike teeth (pi. 77, fig. 4). 

 Eows of small teeth extend inward from the bordering needlelike 

 teeth toward the median line of the triturating surface in its anterior 

 and ventral regions. The outer two or three teeth of each row 

 bear sharp points, the remainder being blunt. The rows often 

 bifurcate as tliej^ approach the center, and the teeth diminish in size 

 toward the center (pi, 77, fig. 3). 



Between the mandibles and the first maxilla, on each side of the 

 median line, is a pyramidal elevation, roughly 4-sided at the base, 

 about 1 mm in diameter, and covered with fine bristlelike hairs. 

 The nasiform process of the labrum fits in between the apices of 

 these pyramids. The bases of the pyramids block the anterior end 

 of the ventral thoracic food groove, but obviously can be separated 

 to permit the passage of nutriment. 



The first maxilla has a strong conical tooth at the anterior corner 

 of its median border, followed by 15 to 20 stout spines. The outer 

 surface of the basal half of the maxillary spines is covered with 

 peculiar flattened spinules, resembling the blade of a dagger, and 

 the terminal half is covered with slender hairs (pi. 79, fig. 5). 



The second maxilla is a small papillalike structure about 1 mm 

 long, located near the base of the first phyllopodium. It is covered 

 with groups of short hairs and bears about 10 plumose setae, which 

 project medially. 



There are 11 pairs of thoracic appendages (phyllopodia), the first 

 pair of which is slightly smaller than those immediately following. 

 Appendages 2 to 7, inclusive, are about the same size, 7 being per- 

 haps the largest. Appendages 8 to 11 decrease rapidly in size, 11 

 lieing about one-half the size of 7. Plate 79, figures 1 and 2, depicts 

 appendages in anterior and median views. The branchial lamina 

 is triangular with serrate borders. The branchial sac (gill) is 

 elliptical in outline. The exopodite is fringed with long plumose 

 setae, shortest near the proximal end and longest (about 1,400/u,) 

 at the distal end. Plumose setae of the same general type arise from 

 the external border of the endopodite (pi. 78, fig. 4). These setae 

 are similar to those of the exopodite but are more distinctly jointed 

 at the base. Thej^ are shortest at the proximal end of the endopodite 

 and longest near the apex, or inferolateral border, where they reach 



