Boone, Crustacea, Cruises of ''Eagle" and ''Ara," 1921-28 41 



primary teeth, the margin is eoncavely excavate, and furnished with 

 nine secondary teeth, similar to the other secondaries. This lateral 

 pair of primaries also has the base elevated or swollen for a short 

 distance back onto the carapace. It is followed on the outer side by 

 a single secondary tooth which in turn is followed on the outer side 

 by another primary tooth whose convex margin extends back to the 

 base of the last primary tooth which is on the lateral margin and 

 extends back as a carina to the base of the telson. 



The rhipidura have the shorter part of the basal article of the ped- 

 uncle with two longitudinal carinae on the upper surface and an acute 

 tooth at the median point of its posterior margin ; the produced inner 

 process is as long as the telson and consists of a subrectangular pro- 

 longation which has its outer lateral margin slightly convex, the inner 

 lateral margin correspondingly concave; the distal end is incised for 

 half the length of the process by a V-shaped incision, the outer angle 

 a curved, acute spine that extends as far as two-fifths the length of the 

 outer blade; the inner angle is an even longer, acute spine which is 

 equal in length to the outer branch of the uropoda, and bears about 

 midway the length of its inner lateral margin a rounded node which 

 thickens with age, in the males especially. 



The inner blade of the uropoda is very narrowly oval and in length 

 extends about one millimeter beyond the node on the long spine of the 

 process ; it is heavily fringed on the entire margin with plumose setae. 

 The outer blade has the proximal article in length extending as far 

 as the second primary lateral tooth of the telson and is thickened in 

 the median longitudinal line, with the inner margin very slightly 

 convex, the outer margin armed along its distal half with nine articu- 

 lated spines, the distal one of which is on the terminal angle and is 

 twice as long as the eighth spine ; the distal article of the blade is two- 

 thirds as long as the proximal and is suboval, half as wide as long and 

 densely ciliate. 



The antennal segment bears on either side of the rostrum a curved 

 process which at its upper distal angle forms an acute triangulate 

 tooth; the ocular segment bears a shorter rounded, outward-directed 

 process on either side. 



The eyes are triangulate, the cornea reniform, set obliquely upon 

 the bulbous stalk. 



The antennulae have the peduncular articles slender, cylindrical, 

 the second and third articles the longer, subequal ; the three-branched 

 flagella slender, multiarticulate. 



