236 AMERICAN JOURNAL 



tion is needed to prove this. As before remarked, these species 

 inhabit districts more and more dry, with longer and hotter dry 

 seasons as we go southward, except on the islands where they 

 are dry but cool. This is the character of the climate close to 

 the coast also. Several of another group are found on the 

 island and edge of coast which partake of the characters con- 

 nected with these peculiarities of climate, viz : paleness beneath, 

 and general light colors. Another striking fact in this southern 

 region is the absence or smallness of the trees, which toward the 

 north accompany every species, and in fact are necessary to 

 their existence. 



As connecting the fidelis group with the next, I refer to those 

 of the same southern habitat which are more conical, nearly im- 

 perforate, and less normal in their bands. They all have the 

 revolving striae, usually very distinct, but in Kellettii assuming 

 the oblique file-like character of the next group. This one alone 

 occurs on the mainland, the other three, which seem like branches 

 from it, are peculiar to islands ( Tri/oni, crebristriata, intercisa ? 

 Carpenteri, which I formerly placed with these, seems nearer to 

 Traskii). These, however, can scarcely be considered more 

 nearly allied to fidelis than to the group of the peninsula inclu- 

 Pandorce, Veatchiana, etc. They stand between but distinct 

 from both. 



The group which seems to inherit the sculpture of Townsen- 

 diana, although ^modified in many of them, commences near 

 where that ends, in a bandless form without wrinkles, and imper- 

 forate, which Newcomb refers to NicJcliniana, although it 

 differs in both these characters and also in a broader lip. I haye 

 before mentioned both this and anachorcta as connecting linFs. 

 This leads to arrosa, the first banded and wrinkled species as we 

 come from the north. From this, branch off by successive gra- 

 dations in form and sculpture, exarata, reticulata, ramentosa 

 Bridgesii, Nickliniana, redimita, and Calif 'omiens is, all so near 

 together in range, and so often intermixed as to seem scarcely 

 more than varieties, as two or three of them undoubtedly are. 

 The second, fourth, and sixth are probably not entitled to specific 

 distinction.* 



Along the coast this group seems to disappear at Monterey, 

 being replaced, southward, by the preceding, to which Califor- 

 niensis forms a passage. In the Sierra Nevada we find it repre- 



* The species of this group being nearly allied and inhabiting nearly the 

 same range, hybrids are not uncommon, but, instead of uniting them, 

 serves rather to prove their distinctness, being very rare in proportion to 

 the numbers of the typical specimens, They occasionally occur, also, be- 

 tween widely different species. See H. tudiculata, P. 



