158 Rowland M. Shelley 



ly and curving apically to subacuminate tip, with or without variable 

 numbers of long, slender barbules scattered along stem distal to midlength 

 curve and clustered apically. Acropodite either acicular, looping over 

 prefemoral process, and without projections, or expanding near midlength 

 and with broad spiniform projection, stem looping thereafter and becoming 

 subacicular. Prostatic groove arising in pit in prefemur, running along 

 medial surface of prefemur onto dorsal or inner surface of acropodite, 

 continuing to terminal opening. 



Cyphopodal aperture broad, encircling 2nd legs, sides and caudal 

 margin elevated above metazonal surface. Cyphopods in situ with 

 valves oriented transversely in aperture, common surface visible in 

 aperture. Valves variable in size, subequal, lightly to moderately hirsute, 

 medial corners gently to strongly extended, subtending slight to moderate 

 central depression. Receptacles moderate-size, alate, with long hairs 

 arising from ventral margin. Operculum moderate-size to large, located 

 lateral to valves. 



Distribution — Occurring in the western periphery of the Columbia 

 Plateau Physiographic Province in central Washington and the northern 

 Rocky Mountains and environs from eastern Washington to western 

 Montana. 



Species — Two. 



Remarks — I (Shelley 1990) stated that in western Canada, the 

 Xystodesmidae did not occur east of the crest of the Cascade Mountains, 

 although there was an outside possibility that the family might be 

 found around Rossland and Trail where the forests seem more moist 

 and extensive. As Montaphe is now known less than 5 mi (8.0 km) 

 south of the International Border in Idaho, it seems certain that this 

 genus is represented in the adjoining part of the interior of British 

 Columbia. 



As envisioned here, Montaphe is heterogeneous; the only features 

 shared by both component species is the rust color, the narrowly 

 segregated gonocoxae, and the general curvature pattern of the elements 

 of the telopodite. To some degree, M. paraphoena represents an abbreviated 

 or shortened version of M. elrodi, with the prefemoral process terminating 

 before the acropodal loop rather than after. The acropodite of M. 

 paraphoena is much broader and the only one in the tribe with a 

 secondary projection, but I think the general pattern of the gonopodal 

 elements of M. paraphoena is similar enough to that of M. elrodi to 

 be accommodated at least temporarily under the same genus, as opposed 

 to erecting another monotypic taxon. The two species are roughly 

 115.5 mi (184.8 km) apart, and the substantial anatomical differences 

 suggest that additional forms may await discovered in central Washington. 



