PEREZ FARFANTE; REVISION OF GENUS PSEUDARISTEUS 



mesial angle slightly produced) lying free but against 

 ventral surface of distolateral lobule. 



Appendices masculina and interna like those of P. 

 kathleenae. In males, plate of sternite XIII flat, 

 ovate but produced in minute apical spine, its length 

 1.8-1.9 basal width; sternite XIV bearing antero- 

 median tubercle or low, anteriorly produced prom- 

 inence. 



Thelycum (Fig. 12A, 5) with setose plate of ster- 

 nite XIV long, transversely depressed (occasional- 

 ly with median elevation), anteriomedian margin 

 straight or slightly convex, plate produced at either 

 side in short anterolateral hood; fossa immediately 

 anterior to plate short and bearing pair of small, 

 oblique, ridges. Median plate of sternite XIII, also 

 covered with setae, moderately long (length 2.9-3.5 

 basal width) but falling distinctly short of spine on 

 sternite XII, rather narrow (maximum width 0.45- 

 0.55 length), lanceolate, tapering anteriorly from 

 near base, occasionally from near midlength, and 

 strongly produced in sharp apical spine; postero- 

 lateral margins of plate, usually turned ventrally, 

 flanked by, or interlocking with, slender ridges 

 curving laterally on margin of sternite XIII. Ster- 

 nite XII minutely setose, strongly raised and crested 

 by median carina ending anteriorly in minute spine. 



Color in life crimson (Wood-Mason 1891). 



Maximum lengths. - 

 mm CL. 



-Males, 29 mm CL; females 37 



Geographic and bathymetric ranges.— From the Gulf 

 of Aden to the Strait of Makassar, Indonesia (Fig. 

 9). It has been found at depths between 741 and 

 1,710-1,730 m. 



Variation.— This species exhibits marked variation 

 in shape of the last 2 articles of the third maxilliped 

 in armature of sternite XIV of males, and also in 

 the shape of the thelycal plate of sternite XIII in 

 females. Those articles range from moderate to very 

 narrow widths and both the proximal and distal 

 parts of the ultimate article may be imperceptibly 

 to conspicuously dilated. Sternite XIV may bear 

 either an anteromedian tubercle or a low, anterior- 

 ly produced prominence. In the few males examined, 

 the presence of a very slender ultimate article of the 

 third maxilliped seems to be correlated with the 

 presence of a prominence, instead of a tubercle, on 

 sternite XIV. Furthermore, in females the thelycal 

 plate of sternite XIII, although always lanceolate, 

 may be broadest near the base, (in most specimens), 

 or as far anteriorly as midlength. 



The female from the Strait of Makassar, Indo- 

 nesia, cited in "Material", was made available to me 



-: -■'■■-  r-^ ' ■'- - f \ ■/■■y:- 



y^^^l^vv^^^^ 



B 



Figure 12.— Psevdaristeus crassipes: A, 9 35 mm CL. off Djibouti, Gulf of Aden. B. 9 3.5 mm CL, Gulf of Mannar, India. Thelyca. 



Scale = 2 mm. 



325 



