HOLOSPIRA. 67 



These snails can tolerate great heat. Living specimens of 

 H. strcbcliana and H. nelsoni sent me survived immersion in 

 actually boiling water for some minutes. Unlike other snails, 

 they did not retract in the water. They probably experience 

 a high temperature in the exposed situations they inhabit. 



The present genus was first indicated by Albers in 1850, as 

 a section of Cylindrella, under the name Acer a. This name 

 being preoccupied, Prof. E. von Martens in 1860 replaced it 

 by the appropriate term Holospira, 'entire spire,' alluding to 

 the retention of the early whorls in this series, while they are 

 generally lost in other members of the family. He included 

 with them some species now referred to Epirobia. The group 

 was elevated to generic rank by MM. Crosse & Fischer in 1870, 

 and we owe to these authors the first information upon jaw 

 and teeth, and the observation that the axis is a hollow tube, 

 as in Ccclocentrmn. 



In 1865 Thomas Bland had recorded the presence of lamelke 

 within the penultimate whorl of //. goldfussi, but no taxo- 

 nomic use was made of this fact until the genus passed under 

 the penetrating eye of Hermann Strebel, 1880. This able 

 observer was apparently the first who was not deterred from 

 cutting shells by the fear of injuring "specimens." His 

 genius for taxonomy grasped the value of the internal char- 

 acters in classification, and upon these characters he based the 

 new groups Metastoma, Bostrichocentrum and Uolospira in a 

 restricted sense. Prof. William II. Dall (1895) amplified the 

 classification along the lines initiated by Strebel; and although 

 there has been a considerable increase in the number of species 

 since his classification was proposed, no material change 

 therein, further than the restriction of Metastoma to its orig- 

 inal limits, has been made in the present work, further re- 

 search confirming his conclusions. 



The monographs of Crosse (Journal de Conchyliologie, 

 1892) and of von Martens (Biologia Centrali Americana, 

 1897) practically ignore internal characters. Though later 

 in date, they are to be classed with the work preceding Strebel. 



Many species doubtless remain to be found. The list given 

 by Crosse & Fischer in 1873 contains 13; Stearns, 1890, has 



