PART 1 GARTH : PACIFIC OXYRHYNCHA 9 



families. In each subfamily of the Majidae as presently constituted, with 

 the exception of the Acanthonychinae, it should be possible to separate 

 on the one hand genera with this character, and on the other hand genera 

 without this character, as Balss has done in the Inachinae with his groups 

 Macrocheiroidea and Camposcioidea. His division of the Pisinae of 

 Alcock into Pisinae sensu restr. and Hyasteniinae, and his separation of 

 the Macrocoelominae from the Mithracinae on the strength of this one 

 character appear inconsistent with the principles expressed and are not 

 herein adopted. Nor do the groupings suggested by the male first pleopods 

 support a division along these lines. Those wishing to make use of the 

 subfamilies of Balss, insofar as they further divide the Pisinae and 

 Mithracinae as here recognized, will find them given as subdivisions in 

 the keys to these subfamilies, where they form natural groupings of 

 genera. 



In addition to the characters proposed by Balss in the work cited, the 

 writer considers of equal importance the shape of the male abdomen and 

 the structure of the male first pleopod. On the strength of these characters, 

 plus some evidence of similarity of larval stages, a new subfamily, the 

 Oregoniinae, has been erected. To Oregonia, type genus and primitive 

 member, are united Hyas and Chionoecetes, which share with Oregonia 

 the broad and deeply inserted terminal segment of the male abdomen 

 and a male first pleopod with filamentous setae. The subfamily is of 

 circum-Arctic distribution, extending into temperate waters on the east 

 and west coasts of North America and Eurasia. Its placement in the 

 systematic arrangement may be questioned ; however, it is the Acanthony- 

 chinae and Ophthalmiinae that are the anomalous groups, the interpola- 

 tion of which should not be allowed to obscure the relationship of the 

 Inachinae through the Oregoniinae to the Pisinae. 



The Parthenopidae have been considered a small and somewhat 

 insignificant family, both in numbers of species and individuals, par- 

 ticularly as represented on the American west coast. That this was due 

 in part to insufficient collecting may be judged from the fact that as 

 recently as 1925 Rathbun had no specimen material with which to illus- 

 trate Parthenope (Parthenope) hyponca (Stimpson), Parthenope (Pseu- 

 dolambrus) triangula (Stimpson), Solenolambrus arcuatus Stimpson, or 

 Aethra scruposa scutata Smith and was obliged to reproduce figures from 

 the early literature. With the exception of the last named species, which 

 is still a rarity, these are now represented among Hancock collections 

 by extensive series from the mid-American mainland, while several species 

 unknown to Miss Rathbun, including Daldorfia garthi Glassell, Hetero- 



