88 U.S. NATIONAL MUSEUM BULLETIN 2 60 



Relationship. — The assignment of this species to a known genus 

 is questionable, even though the diagnoses of several genera might 

 be expanded in order to admit it. It lacks completely the aspect of 

 HippoTnedon B,oeck {—Paratryphosites Stebbing, see Gurjanova, 

 1962) in its slightly reduced, narrowed and tapering coxa 1. Thus, 

 it resembles '•'"TryflioscC auct. {^Lepidepecreopsis Stephensen, see 

 remarks above) and Uristes Dana. It resembles '"''Tryphosa''' more 

 than Uristes in the subequal lengths of articles 5 and 6 of gnathopod 1. 

 But U. perspinis differs radically from members of ''^Tryphosa''' in its 

 small and inconspicuous epistome-labrum complex. This species can 

 be admitted to Uristes only by disregarding the morphology of the 

 gnathopods. There is so slight a difference in length between articles 

 5 and 6 of the type-species, U. gig as Dana {^ViO^j.—TrypTiosa anteri' 

 nipotens Stebbing, 1888), that the small quantitative difference seen 

 in the species at hand seems admissible. But, in addition, Uristes 

 perspinis differs from most other species of Uristes by the ventro- 

 lateral extension of the lateral cephalic lobes, in resemblance of 

 Uristes (?) lepidus J. L. Barnard (1964b). 



J. L. Barnard (1964b) pointed out that Paracentromedon Chevreux 

 and Fage must be studied as a possible synonym of Hippomedon^ but 

 the former genus is paradoxical in its somewhat smaller coxa 1, failing 

 to cover the head as fully as in typical species of Eippomedon. Coxa 

 1 of Paracentromedon^ however, is not as small as in the type-species 

 of Uristes or in U. perspinis. Hence Paracentromedon seems to inter- 

 grade Uristes and Hippomedon. 



Uristes perspinis has a bulbous dorsoposterior process on pleonite 3, 

 a character occasionally occurring on species of '"''TrypUosa^'^ such as 

 '■'^TrypJiosa'''' { = Lepidej)ecreopsis) hiloha (Stephensen, 1925), "2"." 

 triplans J. L. Barnard (1962a) and 'T." quadrata J. L. Barnard 

 ( 1962a) . Uristes perspinis differs from those species by the smallness 

 of the labrum-epistomal complex and the shape of the lateral cephalic 

 lobes. 



Uristes (?) lepidus and U. {'i) perspinis presumably are congeneric 

 but like Amiasiopsis fomes, new species, they are inadmissable to 

 existing genera without extensive diagnostic revisions of those genera. 

 The remarks here supplement those written under Amtasiopsis fomes 

 and under the heading "Lysianassidae." None of the three species 

 mentioned above is assignable to ScMsturella Norman because of the 

 unconstricted rami of uropod 2 and the presence of a few molar setules 

 (see table 1) . The assignment of A. fomes to '■'■Trypliosd''' is ruled out 

 because the labrum and not the epistome dominates the prebuccal 

 complex. Indeed, the real problem is whether '■''Trypliosa^'' Uristes^ 

 and Amhasiopsis are distinct from one another. J. L. Barnard 



