STREPTAXID^E. 51 



Mr. John W. Taylor has recently separated a new group under 

 the name of Gonaxis ; he thus characterizes it : 



" Shell pupiform, uns3^mmetrical, axis of the apical whorls 

 directed to the right, lower aspect of penultimate whorl of a 

 somewhat triangular shape, forming a prominent hump on the 

 left side. 



" The most important character of this genus is the deflection 

 of the upper or apical whorls, whereas in Streptaxis it is the last 

 whorl only that is diverted from the perpendicular. This pecu- 

 liarity appears to me to be of sufficient importance to warrant 

 the erection of this genus." 



The type of Mr. Taylor's new genus is represented on Plate 

 14, figs. 82, 83. The apparent peculiarity to which he alludes is 

 shared more or less by several other species of elongated 

 Streptaxis, and the recognition of the group as valid can scarcely 

 serve a useful purpose. 



Speaking of the Indian species, Mr. W. T. Blanford writes : 

 "All the species of Streptaxis are somewhat variable, and with 

 a large collection from South India it would probably be found 

 that many intermediate varieties occur. As a rule, the general 

 form appears more constant than any other characters, and the 

 teeth in the mouth vary considerably. The parietal lamellae are 

 peculiarly inconstant." 



Eustreptaxis is undoubtedly the typical group of the genus, 

 whilst Artemon, Scolodonta, etc., possessing depressed helicoid 

 shells, regular in volutions, are aberrant forms, not readily dis- 

 tinguished, conchologically, from certain species of true Helices ; 

 yet for the purpose of preserving the transition from Streptaxis 

 to Ennea, I am forced to commence this monograph with these 

 aberrant instead of typical groups. As the deflection of the 

 whorls is really an adult character, it follows that in young 

 shells the volutions are regular; a fact which is very apt to 

 mislead an inexperienced conchologist ; Artemon may be re- 

 garded as an arrested development of Streptaxis, the shell 

 becoming adult with the persistence of juvenile characters. 



Section ARTEMON, Pfeiffer. Shell heliciform, rather flattened, 

 whorls regular, aperture without teeth, outer lip often slightly 

 thickened and expanded or subreflected. South American. 



