378 BULLETIN" 10 0, UNITED STATES NATIONAL MUSEUM 



not uniting two subgenera or genera to form one, but on the contrary 

 was retaining both groups, merely suppressing one of Ferussac's 

 names in favor of a new designation. 



Subsequent authors, Pfeiffer (1841-1877), Gray (1847), Albers, and 

 the Adams brothers, all kept Helicostyla and Cochlostyla separate in 

 different genera or supergeneric categories. Pfeiffer, it may be noted, 

 in the first part of his Symbolae 4 recognized Cochlostyla Ferussac as 

 one of his 18 valid genera, going still further in his restriction of the 

 group than Beck, while Helicostyla he submerged in Helix. Later, 

 however, in the same work he united Cochlostyla with Bvlimus. 



Von Martens, in his version of Albers' work 8 was the first one to 

 unite these two groups into one genus, which he called Cochlostyla, 

 making Helicostyla the second subgenus under it. Hence von Martens 

 is to be considered the first reviser, and the name he chose for the 

 genus will stand according to Article 28 of the International Rules. 



Thereafter, for 35 years, Cochlostyla was universally used for this 

 group by such authors as Dohrn, Kobelt, Clessin, Nevill, Hidalgo, 

 Semper, von Mollendorff, Fischer, E. A. Smith, Fulton, and Pilsbry 

 (1891). 



In 1895, however, Pilsbry, in his "Guide to the Study of the 

 Helices" 6 made Helicostyla the name of the genus in place of Coch- 

 lostyla, because of its prior position in Ferussac's work and because of 

 Beck's restriction and use of the subgenus Helicostyla. But we have 

 shown that Beck maintained both groups equally, merely changing 

 the name of Cochlostyla for some reason to Orthostylus. Both groups 

 remained equally a heterogeneous mixture, Helicostyla containing 

 three species of Cochlostyla and five of Cepolis, while Cochlostyla in- 

 cluded seven species of Cochlostyla and seven of Amphidromus, besides 

 an Ampelita and a Caryodes. 



The first type designation for Helicostyla is apparently that of von 

 Martens, 7 who cited Cochlostyla mirabilis Ferussac as type. Gray's 

 designation of the same species might be considered questionable, as 

 he uses the combination Helicostyla Beck, 1837. The first designation 

 of Cochlostyla seems to be that of Pilsbry, 8 who named Cochlostyla 

 metaformis as type. 



I shall not discuss specific problems in this introduction, preferring 

 to treat these under the species that present points of particular 

 interest. I have been largely influenced by problems of distribution 

 and factors of isolation producing fixation, and the forms here named 

 are zoogeographic races and not merely individual variations of size, 



' Symbolae ad historian! heliceorum, vol. 1, pp. 5, 21, 1841. 



• Die Heliceen, ed. 2, p. 173, 1860. 



• Man. Conch., ser. 2, vol. 9, pp. 217-218, 1895. 

 » Albers, Die Heliceen, ed. 2, p. 175, 1860. 



» Nautilus, vol. 46, p. 71, 1932. 



