270 



PROCEEDINGS OF THE ACADEMY OF 



[Mch., 



altitudes. To attain a true idea of the relationships of any given alti- 

 colous dwarf it is essential to know the forms of the lower canyons of 

 the same region. 



The first step toward a fundamental knowledge of the races and 

 species of Oreohelix must be the study and definition of races in the 

 broad sense above indicated. In my opinion, the minor modifications 

 can be so overnamed that the wider distinctions become altogether lost, 

 as in the Utah series. The field is vast, and for many years to come 

 there will be plenty of room for work. Anybody who secm-es a good 

 series of the forms of any district can materially help the cause by 

 working them up. 



The sculpture of the embryonic shells and the genitalia seem to afford 

 the most important characters for specific classification. It would , 

 take us too far afield to discuss the entire mass of data at hand. This 

 must be reserved for another occasion. Only forms from central and 

 southern Arizona and New Mexico are dealt with below.' The meas- 

 urements of the ge-nitalia in millimeters follow : 



Species 



Penis 



Epi- 

 phallus 



Vagina 



Sperma- j t^ . , 



'hprn nnA , ' ' 



shell 



theca and 

 duct 



Mus. 

 No. 



0. strigosa, Pecos 



0. elrodi 



0. s. huachucana 



0. harhaia 



0. yavapai 



O. y. neomexicann 



18.5 

 22.5 

 21 

 13.5 

 15-16 

 15 



85,100 

 79,475 

 83,370 

 87,011 

 79,415 

 80,700 



The species thus far dissected show considerable differences in the 

 genitalia, chiefly in the proportions and shape of the penis, the forms 

 falling into three groups, as follows: 



' For comparison with the southern forms I have, however, figured the anatomy 

 of 0. elrodi (Pils.), from Montana, PI. XIX, fig. 2. The penis is like that of O. 

 strigosa, from Pecos, the lower third having thick walls, densely plicate within; 

 above that the walls are thinner, densely lined with long papillse, and in the upper 

 third there are several low fleshy ridges, also papillose. There is an extremely 

 short, conic penis-papilla in the apex. The vas deferens enters the epiphallus 

 centrally. The vagina is much dilated and muscular above. The uterus is pro- 

 vided with muscular strands forming an incoherent protractor muscle (fig. 2, 

 r.u.). The embryos were packed in like coins except the two lower ones. The 

 dimensions are given in the table. 



