PART 1 garth: pacific oxyrhyncha 135 



In a personal communication, Josephine F. L. Hart (Mrs. C. G. 

 Carl) states that the zoea of Oregonia gracilis is very similar to those of 

 Hyas araneus and H. coarctatus, both of which are quite different from 

 those of Chorilia longipes and Scyra acutifrons of the Pisinae, species 

 which she has hatched. Full taxonomic weight should be accorded this 

 important developmental consideration. 



Distribution circum-Arctic, extending to north temperate waters of 

 both Pacific and Atlantic oceans. That this subfamily formerly enjoyed a 

 more extensive range is indicated by Imaizumi (1952, p. 179), who 

 reviews the genus Hyas and reports fossil species from the Helvetian of 

 Austria, the Wakkanai of Japan, and the Sahelian of Oran. These are 

 middle to upper Miocene formations. 



Key to the Genera of the Subfamily Oregoniinae 

 la. Carapace considerably longer than broad; rostrum elongate. 

 Cheliped of adult male either longer than walking legs, or very 

 little shorter; ambulatory legs subcyclindrical. Male abdomen 

 with sixth segment increasing in width distally. 

 2a. Carapace subtriangular or suboblong. Postorbital spine 

 remote from eye, affording no concealment. First movable 

 article of antenna not broadened and flattened. 



Oregonia 



2b. Carapace lyrate, hepatic lobe prominent. Postorbital tooth 

 closer to eye, cupped, affording partial concealment. First 

 movable article of antenna broadened and flattened. 



Hyas 



lb. Carapace either broader than long, or very little longer than 



broad ; rostrum short. Cheliped of adult male much shorter than 



walking legs; ambulatory legs compressed. Male abdomen with 



sixth segment decreasing in width distally. . Chionoecetes 



Genus OREGONIA Dana 



Oregonia Dana, 1851a, pp. 270; 1851b, p. 431; 1852, p. 105; 1853, p. 

 1421. Rathbun, 1925, p. 70. 



Type: Oregonia gracilis Dana, by subsequent designation of Miers 

 (1879c, p. 646). 



Description: Carapace subtriangular or suboblong, moderately convex 

 and tuberculate ; a large postorbital, but no preorbital spine ; rostral spines 

 slender. Antennae visible in dorsal view at sides of rostrum, basal article 

 narrow. Merus of maxillipeds distally truncate, bearing the palpus at its 



