1890.] MARINE MOLLUSC.V OF ST. HKLENA. 299 



be inclined to place this form in the Actfeonidce, as recoiiiiTiencled bv 

 Adams, ratlier than in the Pyrum'ulellida-. 



Some confusion appears to exist with regard to the genus Mono- 

 ptijgma, judging from the variety of shells which have been placed 

 in it. The original type described by Lea under tlie name of M. 

 alabamensis is a fossil, and evidently allied to Ancillaria, with which 

 it is associated both by Tryon and Fischer in their recent Manuals. 

 A. Adams published a monograph of this genus in the ' Proceedings 

 of the Zoological Society ' for 18.51 (reproduced in Sowerby's ' The- 

 saurus Conchyliorum,' vol. ii.), including in it a number of species, 

 none of which, in fact, have any relationship with Monoptygma. 

 He subsequently removed all of these species to other genera, with 

 the exception of M. striatum and M. fulvum. A species very 

 closely allied to these forms has since been described by Lischke 

 from Japan, under the name of M. eximium. As far as I can 

 ascertain, no generic or subgeueric division has l)een j)roposed for 

 these species. If as much latitude in variation of form be allowed 

 in the genus Leucotina as in some other genera (e. g., Miirex, 

 Triton, Mitra, &c.), there is no occasion to establish a new division 

 for these three and allied species, for, with the exception of being 

 more elongate than typical species of the genus, they do not offer 

 any material differences in regard to the aperture, sculpture, or the 

 apical whorls. 



Umbrella mediterranea, Lamarck? 



This well-known IMediterraneau shell also occurs at Madeira and 

 the Cape de Verde Islands, but it has not previously been recorded 

 from so southern a locality as St. Helena. Krauss' quotes U. indica 

 as a Cape species, so that I am uncertain whether the two y'oung 

 shells from St. Helena should not be Jeferred to that species, if in 

 reality it is distinct from the Mediterranean form. It is stated by 

 Eydoux and Souleyet, in the 'Zoology of the Bonite,' that the 

 animals do not differ, and, as far as I have studied the shells, the 

 two typical forms appear to pass one into the other. 



Tylodina citrina, Joannis. 



Tylodina citrina, Joannis, Mag. de Zool. 1834, pi. 3ti ; Grube, 

 Ausflug Triest und Quarnero, pp. 58 & 120. 



Hub. Mediterranean (Joannis, Grube, Monterosato, i^c.) ; Canary 

 Islands (Mc Andrew, teste Webikauff). 



Only some small specimens, about 7 rniUiuK in length, were ob- 

 tained. They agree in every particular with the apical portion of 

 large Mediterranean examples with which I have comjiared them. 

 The minute nucleus consists of about two spirally-coiled whorls, is 

 glossy, vitreous, and laterally incliued. 



• fSiidafr. Moll. ii. Gl'. 



