320 . 



THE GENERA PSEUDOLIVA AND MACRON. 



By tames COSMO MELVILL, M.A., F.L.S. 



(Read before the Society, March ii, 1903). 



The genus Fseudoliva, instituted by Swainson in 1840, and having 

 precedence over Gastridium Sowerby {iioti Modeer) has been main- 

 tained entirely upon conchological grounds, the- animal being then, as 

 now, practically unknown. The opercula, however, of two or three 

 species being fo,und to differ fundamentally inter se, Messrs. Henry 

 and Arthur Adams separated^ the Western-American species jP. 

 kellettii H. Ad. and P. cethiops Reeve from the typical P. plumhea 

 Chem., the Swainsonian type of the genus, under the name of Macron, 

 this being at first employed only subgenerically. 



It is worth while here to reproduce their diagnosis in its entirety. 



"Fam. Muricidce. Sub-fam. PurpJirince" 



"Genus Pseudoliva Swainson. 



"Shell ovate, solid, subglobose; spire very short, suture slightly 



channelled, whorls tumid round the upper part; aperture oval, canal 



very short; inner lip arcuated, with a callosity at the hinder part; 



outer lip thin, furnished at the fore part with a small tooth or callosity. 



"Syn.: Gastridhiin ?)0\\., notyiodietY. Gastridia Grdij. 



Pseudodactylus Herm . 



"Ex. P. IcEvis Martini. 



''Pseudoliva, known only by its shell and operculum, reminds one of 

 Olivancillaria among the Dactylidce, but is distinguished by its large 

 Purpiira-Vike operculum, and the tooth on the outer lip. The species 

 are few in number, and come from Africa and California. 



Icevis Mart. 

 sepivienta Rang. 



striata A. Adams. 

 zebrina A. Adams. 



Subgen. Macron H. & A. Adams. 

 "Inner lip with the callus defined; columella obliquely wrinkled; 

 spire elevated, suture channelled. 



Mthiops Reeve. | Kellettii A. Ad." 



Mr. G. B. Sowerby, in his monograph of the genus, enumerating 

 eight species (inclusive of Eburna australis Swb.), makes the following 

 remarks : — 



They — the Pseudolivce —^xQ^oxii a pretty natural group of buccinoid 

 shells, which have a groove encircling the lower part of the whorls, 

 and generally terminating at the edge of the outer lip in a sort of 

 obtuse tooth. A canal is formed at the upper angle of the aperture 

 by the swelling of the outer lip, and a kind of callus on the columella, 

 and the anterior part of the aperture is, in nearly all the species, 

 deeply notched. The columellar lip is thickened over the body 

 whorl. Operculum horny vyith central nucleus. 



I H. ife A. Adams, "Genera of recent Mollusca," vol. i, pp. 131-132. 



