Boone, Crustacea, Cruise of "Alva," 1931 65 



slightly smaller and closer together, sometimes being confluent or 

 obsolete; the outer pair are wide triangles and are separated by a 

 distinct notch from the preorbital tooth which is also triangular and 

 subequal to the outer frontal tooth; the superior orbital border has 

 two closed sinuses, with the margins slightly dentiform at the points ; 

 the outer orbital spine is acute, triangular. The inferior orbital bor- 

 der has one sinus near the outer angle and is produced substantially 

 in advance of the orbit, so that the latter has a dorsal inclination. 

 The inferior inner orbital tooth is triangular, subequal to the outer 

 orbital and very prominent dorsally, being far in advance of the 

 superior tooth. The median, spinelike process of the epistome is also 

 very strong and projects far in advance of the submedian frontal 

 teeth and between them. The anterolateral margins are long, sloping 

 obliquely, very little convex and cut into eight teeth in addition to 

 the postorbital tooth ; the first eight teeth are short, wide, triangulate, 

 with acute tips, the posterior four being slightly larger than the 

 anterior three teeth, while the last or lateral tooth is four or five times 

 as long as the preceding one and quite acuminate; the posterolateral 

 margins are about as long as the anterolateral margins, smooth, con- 

 cave, forming a curve confluent with the posterior margin, which is 

 smooth in young specimens, but finely carinate in very large ones. 

 The interstices between the anterolateral teeth are filled with short, 

 coarse setae. The regions of the carapace are not especially deline- 

 ated, except the urogastric and cervical depressions. The entire dorsal 

 surface of the carapace is covered with coarse miliary granules ; there 

 are two transverse lines of these granules on the gastric region, and on 

 the branchial, there is, one on each side, a curved line of granules 

 extending inward from the lateral tooth. 



The epistome is quite linear, produced into the above described 

 median spine. The buccal cavern is squarish, a trifle wider than long. 

 The efferent branchial channels are sharply defined. The sternal 

 plastron is smooth, the male belt is triangular, with the second and 

 third segments transversely carinate; consisting of five articles, the 

 second, third and fourth articles being fused. The female belt is 

 seven-segmented, widely ovate. 



The eye is dorsal in position, with a very short stalk and large 

 hemispherical cornea, set obliquely terminal and possessing excellent 

 peripheral vision. 



The antennulae are very slender and fold obliquely within the 

 f ossett, which is well separated by the thick septum, immediately below 

 which the spine of the epistome projects. 



