THE SPIDER CEABS OF AMERICA 259 



Hyas latifrons Stimpson, Proc. Acad. Nat. Sci. Philadelphia, vol. 9, 1857, 



p. 217 [24] (type-locality, in Mart Beringiano; types, Cat. No. 2100, 



U. S N. M.); "Smithson. Misc. Coll., vol. 49, 1907, p. 9, pi. 2. 

 Hyas coarctatus, var. latifrons Braznikov, ]M6m. Acad. Imp. Sci. St. Peters- 



bourg, ser. S, vol. 20, 1907, No. 6, p. 43. 

 Hyas coarctatus alutaceus Birula, Mem. Acad. Sci. St. Petersbourg, ser. 8, 



vol. 29, 1910, p. 4, pi. 1, figs. 2-5. 

 Hyas coarctatus forma alutacea Dons, Troms0 Mus. Aarshefter 37 (1914), 



1915, p. 86, footnote. 

 Hyas coarctatus ursinus Rathbtjn, Proc. U. S. Nat. Mus., vol. 64, art. 14, 



1924, p. 4 (type-localit}', Sea of Japan, 325 fathoms; holot3'pe, female. 



Cat. No. 46493, U. S. k. M.). 



Diagnosis. — Carapace lyrate; postorbital and hepatic regions di- 

 lated laterally, forming a winglike expansion w^th a rounded, postero- 

 lateral angle. Basal antennal article narrowing anteriorly but not 

 triangular, and without large tubercle (fig. 90, h). 



Description. — The hepatic and postorbital regions are dilated 

 laterally and form an expansion with a broadly rounded postero- 

 lateral margin, which is separated by a broad and deep sinus from 

 the branchial region. The tubercles of the lateral margin extend 

 foi'^'ard only to the posterior part of the hepatic region. The basal 

 article of the antenna narrows a little forward, its thickened side 

 margins are granulate, the outer margin terminating forsvard in a 

 distinct although blunt tooth. 



The ornamentation of the carapace is similar to that of II. araneus. 

 On the mesogastric region two large median tubercles, on the uro- 

 gastric region two others side by side. In the old the carapace is 

 rougher than in araneus, and the chelipeds more roughly granulate. 

 The rostral horns may be contiguous or diverge narrowly or have a 

 buttonhole gape, meeting only at the tips. The chelipeds may 

 attain or exceed the length of the legs of the first pair. 



Color. — According to Leach's figures, the color is similar to that 

 of H. araneus, but the red of carapace and chelipeds is more re- 

 stricted. Dusky brick-red above, whitish below (Stimpson, as 

 latifrons) . 



Variations. — In the course of its range, the species shows great 

 variation. The typical form is of relatively small size, has a long 

 rostrum in proportion to length of carapace; rostrum contained in 

 total carapace length 4.5 times in specimens of medium size, to 6.4 

 times in the largest (Birula). The form called alutacea by Brandt 

 and later latifrons by Stimpson has a shorter, broader rostrum, its 

 length contained in total carapace length 7 times in specimens of 

 medium size, to 9.3 times in large specimens. The anterior third of 

 the carapace, embracing the hepatic regions, is wider in alutaceus 

 than in typical coarctatus; the tubercles of the carapace are less 

 strongly marked. 



