176 LIGUUS CORONA. 



This group is still unknown anatomically. In shell-characters it 

 seems more nearly allied to Hemibulimus than to other known sub- 

 genera of OrthalicincB) agreeing with that group in the vertically 

 wrinkled nepionic shell, the deeply excised inner lip, and the truncate 

 columella. It differs from Hemibulimus in the brighter coloration, 

 and heavily calloused columella. The structure of the columella is 

 remarkably like some species of Metorihalicus, a group distinguished 

 by its pitted apical sculpture, and thick outer lip. 



Albers, Pfeiffer, Shuttleworth, von Martens and others have in- 

 cluded a greater or less number of incongruous species in Corona. 

 Excluding these, the subgenus consists of a group of very closely 

 allied forms, which when full geographic series are collected and 

 studied may prove to be varying races of a single species. Cousin 

 has taken this view (Bull. Zool. Soc. France, vii, 1889, p. 193); 

 but the obvious errors of fact and crudities of judgment everywhere 

 apparent in his "Fauna Malacologique de la Republic de PEquateur," 

 and particularly so in his paragraphs upon Corona regina, do not 

 recommend his views to us. 



The distribution of several of the forms is involved in obscurity. 

 L. regaiis, with its variety loroisianus, is known to be a species of 

 the upper Amazon, in Eastern Peru and Ecuador, and western Brazil, 

 L. incisus inhabits the forests east of the Cordillera in Bolivia, and 

 apparently occurs also in the province of Bahia and in Guiana. This 

 is a wide range, and the identity of the Guiana shells with those of 

 Bolivia is not absolutely certain. Of L. perversus I have an appar- 

 ently authentic specimen from Demerara ; but no habitat is yet 

 known for the typical L. regina. 



When the wide gaps in distribution indicated above are narrowed, 

 and large series from single localities are collected, the number of 

 species and their limits may become clear to us. Meantime these 

 are open questions; and in declining to "lump" them I should not 

 be understood as holding the opinion that the forms are distinct 

 species ; I merely desire to leave the subject in convenient order for 

 those who come after. To this end the several forms have been dis- 

 criminated and the whole literature rearranged. Should the group 

 be reduced to a single species, the name perversus Swains., will take 

 precedence over regina Fr. for the whole assemblage. 



There are several names similar to Corona, and of earlier date, in 

 use in zoology. If the molluscan group-name be considered pre- 

 occupied by any of them, it may be called Paraliguus. 



