1915. 



NATURAL SCIENCES OF PHILADELPHIA. 



339 



(3) Three lamellae, superior, axial and basal. 4 specimens = 20%. 



Length 13.9, diam. 3.7 mm.; whorls 15^ 

 " 13, " 4 " " 14 



Station 1, northern and eastern sides of Teocalli Butte, at the 

 base of the cliff. Types Nos. 112,265, A. N. S. P. 



Twenty shells opened out of a series of over 250 show that the 

 bilamellate form predominates. The largest shell noticed is 14.9 

 mm. long, the smallest 14.5 mm. There is rather wide variation in 

 sculpture, but a large majority of the shells conform to fig. 3a in 

 this respect. 



Holospira bilamellata insolata n- subsp. Plate VII, figs. 4 to 4a. 



The shell is slender, with a rather long terminal cone; very strongly 

 ribbed throughout; composed of many (13^ to 17|) short, convex 

 whorls, the last very shortly free in front. Peristome narrow, only 

 very slightly expanded. Only the axial lamella developed in 14 

 out of 16 individuals opened, the other two having axial and basal 

 lamellae. 



Length 15.5, diam. 3.6 mm.; whorls 17^ 



161 

 16* 

 16* 

 15* 

 15i 

 15 



15| 



14 



13| 



13| (axial and basal lamellae). 



Station 6, on the southeastern slope of the mountain south of 

 Big Hachet Mt. 



This form differs from crossei and mearnsi by the more slender 

 shape, long terminal cone, more numerous whorls and strong sculp- 

 ture. It agrees with bilamellata in having many whorls, but differs 

 by its slender form, longer cone, the prevalence of unilamellate 

 shells, etc. H. b. heliophila stands nearest to insolata, but in that 

 race the bilamellate form predominates. It is more conspicuously 

 ribbed than any of the other Hacheta races. 



Holospira bilamellata media n. subsp. Plate VII, figs. 5 to 5c. 



The shell is cylindric with a long terminal cone ; composed of many 

 closely coiled, convex whorls, all after the embryo rather strongly, 



