600 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



postlaterally. Second segment 1 mm. long. Second, third, and 

 fourth segments subequal, fifth, sixth, and seventh segments nar- 

 rower and subequal, the lateral margins decidedly, acutely produced 

 into a toothlike process; epimera completely coalesced with seg- 

 ments, but with line of fusion very distinct. 



Legs: All six pairs are ambulatory, subequal, similar in structure; 

 the third, fourth, and fifth joints are heavily fringed along the inner 

 margin ; the dactyl of each is distinctly bifid. 



Abdomen: This is biarticulate ; the first five segments are fused, 

 the first is entirely and the second almost entirely hidden by the 

 thorax ; three suture lines on either side mark the areas of the third, 

 fourth, and fifth segments, respectively; these suture lines are lost 

 on the median region; the terminal segment is smooth, domelike, 

 with two indistinct blunt tubercles posteriorly ; the postlateral mar- 

 gin is triangularly produced, pointed acutely at the median ex- 

 tremity and with a distinct, small, pointed tooth on either side of 

 the median point. The uropoda are shorter than the terminal seg- 

 ment, the immovable inner branch is the larger, and has its outer 

 postlateral angle truncate; the inner movable branch is three-fourths 

 as broad, lanceolate, and with its outer postlateral angle very acute 

 and the entire outer branch minutely crenulated on the lateral 

 margins. There are five pairs of pleopoda, which are biramous and 

 heavily fringed with fine hairs. 



The holotype (Cat. No. 50404, U.S.N.M.) was collected at Ca- 

 banas, Cuba, by Dr. Paul Bartsch and Mr. John B. Henderson, of 

 the Tcrnias Barrera Expedition to Northwestern Cuba, 1914. (Coll. 

 No. 512.) 



This species is readily recognized by the unique sculpturings of 

 its domelike telson. 



Suborder IDOTHEOIDEA. 

 Family ARCTURIDAE. 



ASTACILLA CALIFORNICA. new species. 



Plate 89, fig. 1. 



Body narrowly elongated, 6.1 mm. long, exclusive of antennae, 

 and 2.2 mm. wide. A distinct median dorsal ridge is present, which 

 attains its greatest prominence in a bluntly conical tubercle on the 

 anterior part of the fourth thoracic segment. Segments decidedly 

 convex dorsally. Fourth thoracic segment two-fifths the length of 

 entire body. Sutures deeply constricted. 



Head slightly wider than long (0.9 mm., 0.75 mm.), with decided 

 anterior excavation between the produced anterolateral angles; lat- 

 eral margins lobate, swollen anteriorly by prominent ocular lobes. 

 Eyes composite, suboval, 9.6 mm. long., situated anterolaterally. 



