THE NAUTILUS. 113 



Strebel and Pfefter, von Martens and Crosse and Fischer, toward a 

 better understanding of it. 



With all of this good work, there has remained a vast amount of 

 confusion. Thus authors almost universally separate Orthalieus as 

 a family distinct from Bulimulidce ; but, in reality, it constitutes 

 merely a generic group of that family. No anatomical or shell 

 character can be shown, of greater than generic value, between 

 Orthalieus and Drymceua. 



Again, the genus "Bulimus" of all authors contains forms belong- 

 ing to two families Helicida- and Bulimnlidfc. 



The forms generally grouped under the name Bidimulus have 

 been shown by von Martens to fall into two groups, based on the 

 character of the jaw: Bulimulus and Otostomus. Crosse and 

 Fischer have made the same division, calling the two groups Ortho- 

 tomiiim and Goniognathmus. These correspond to the two Martens- 

 ian groups, the first having a vertically plaited jaw, the second has 

 the plates angularly converging toward the middle. 



Binney has shown that there exist two styles of teeth, and these 

 correspond to the two forms of jaw, and constitute a far more useful 

 character, as the jaw forms intergrade prettv completely. 



It has not hitherto been noticed that there are certain characters 

 in the shells, and especially in the sculpture of the apices, by which 

 the two groups, or genera, may be distinguished. 1 



In the following synopsis, the leading sections are enumerated, 

 arranged as they fall into groups according to the sculpture of the 

 apices. Of course it is not proposed to base a classification on this 

 single character. 



Certain rectifications and substitutions demanded by the law of 

 priority, and by the proper restriction of the subgenera to species 

 allied to their types, have been made. 



Genus Bulimulus Leach, 1814. 



The species of Bulimulus are terrestrial snails, sestivating or hy- 

 bernating in the ground, crawling on the ground or on plants in 

 damp weather. There are three distinct types of apical sculpture, 

 as follows: 



'The only especial notices of the apical sculpture of Bnlimuli which I have 

 noticed are by the writer, Nautilus, viii, 1894, p. 35, and by Dall, Proc. U. S. 

 Nat. Mus., xvi, 1893. Martens also figures a few apices on the last plates of 

 the " Biologia." 



