342 . PROCEEDINGS OF THE ACADEMY OF [May, 



Length 12.6, diam. 4 mm. ; whorls 13| 

 " 12.5, " 4 " " 121 



" 11.3, " 4 '' " 12; anaxiallamella. 



These shells connect H. crossei and H. bilamellata. Specimens 

 of intermediate size agree exactly with one of the type lot of mearnsi, 

 kindly lent from the National Museum. The smallest shells are 

 indistinguishable from crossei, while the largest could not be separated 

 from small hilamellata. Yet the colony as a whole has a certain 

 individuality by its intermediate size, and as the form has been named, 

 we let it stand as a convenient place for crossei-hUameUata inter- 

 grades. It is attached to H. bilamellata rather than to H. crossei, 

 because the prevalent form, in the small lot opened, is bilamellate. 

 All of the shells were collected in one spot where the writer sat 

 resting. A large quantity could have been gathered had time and 

 strength permitted. A few specimens are quite finely striate, 

 while others are rather coarsely ribbed, like the type of mearnsi; 

 still others being intermediate in sculpture. The sculpture in 

 some shells becomes very much weaker on the penultimate and 

 next earlier whorls. 



H. mearnsi served as monotype of the subgenus Haplostemma 

 Dall, characterized by the possession of an axial lamella only. Bartsch, 

 opening another specimen, found a basal lamella also, and concluded 

 that that lamella had been broken away in opening the original 

 specimen. Since some fully adult examples are known to have an 

 axial lamella only, it is likely that Ball's original diagnosis was 

 correct for the specimen he opened, while Bartsch was also right 

 as to the shell he examined and which we have seen. 



Holospira crossei Dall. Plate VII, figs. 7 to 7c. 



Holospira crossei Dall, Proc. U. S. Nat. Mus., XVIII, 1895, p. 3; XIX, 

 1897, p. 348, PL 31, fig. 2. Pilsbry, Man. of Conch., XV, p. 92, PI. 23, 

 fig. 75; Moll. S. W. States, ii, Proc. A. N. S. Phila., 1905, p. 217, PI. 26, 

 fig. 8. Bartsch, Proc. U. S. Nat. Mus., XXXI, 1906, p. 137. 



All of the above references were based upon 'the original lot, of 

 which there are 11 perfect specimens in Coll. U. S. Nat. Mus. and 2 

 in Coll. A. N. S. P. One of these two has a very weak, hardly notice- 

 able fold on the axis, the other has a very strong but short fold 

 there. 



The writer collected H. crossei at the type locality, the summit 

 of Hacheta Grande. The exact spot, Station 11, is just off the 

 western edge of the small level tract at the summit, which is marked 

 by a small stone monument. Being much higher, this station is 

 less dry than Station 5, where the large H. bilamellata abounds, and 



