Boone, Crustacea, Cruise of ''Alva," 1931 75 



orbital tooth is slightly the largest of the series, the second and third 

 teeth being almost as large, while the fourth tooth is conspicuously 

 the smallest of the series; the fifth tooth being almost as large as the 

 third and more acuminate, with a beaded carina running inward from 

 its apex entirely across the carapace. The urogastric groove is deep 

 and confluent on either side with the groove that defines the cardiac 

 region and terminates anteriorly at the above-mentioned transverse 

 ridge. Between the postorbital tooth and the second tooth there is a 

 beaded line that curves inward to a point behind the preorbital tooth 

 where it unites with a prominent transverse beaded carina that ex- 

 tends completely across the mesogastric region. Anterior to this there 

 is an interrupted beaded carina that arises from the same point as does 

 the preceding carina, but curves forward, forming a short arc with the 

 ends directed backward and is interrupted for a distance equal to the 

 width of the submedian pair of frontal teeth and then forms a similar 

 arc on the other half of the carapace. Anterior to this and halfway 

 between it and the frontal margin are a pair of short curved carinae, 

 that somewhat resemble the submedian pair of teeth. Except for mar- 

 ginal bare spaces adjacent to the ridges, the entire dorsal surface of 

 the carapace is finely tomentose, as are also the sidewalls of the cara- 

 pace. The sternal plastron is smooth. The male belt is triangular, 

 narrow, composed of five segments, the second to fifth segments inclu- 

 sive being fused. The female belt is shield-shape, with the lateral 

 margins a series of scallops, due to the curvature of the lateral margin 

 of each segment; it is composed of seven segments, the first of which 

 is nearly concealed ; the second and third segments are hinge-like ; the 

 fourth, fifth and sixth segments successively increase in length ; the 

 seventh article is a small, shallow triangle. The eggs are very minute, 

 a single female carrying 8000 to 10,000 in a clutch. 



The eye has a short, calcareous stalk and a moderately large hemi- 

 spherical cornea, set obliquely-terminal. 



The antennulae fold almost transversely within the f ossett ; the in- 

 terantennulary septum is wide. The outer, lower margin of the fos- 

 sett forms a wide scallop, not unlike the frontal tooth above it. 



The antennae arise beneath the sixth frontal tooth and lie within 

 the sulcus between the preorbital tooth and the ridged granular proc- 

 ess that arises from the first peduncular segment and completely fills 

 the orbital hiatus; the second and third peduncular articles are short, 

 bulbous ; the flagellum is multiarticulate, about one and one-half times 

 the long diameter of the orbit. 



