KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 50. N:0 5. 9 



ÅiiLiuropsis MÖRCH 1857. 



Shell with minute spiral strise and fine lines of growth, covered by a yellowish, green- 

 ish or brownish cuticula; columellar callus uniformly spread över the inner wall of aper- 

 tiire (forming no pads). H. 20 — 40 mm. 



A. islandica (Gmelin 1783). 

 (= Natica helicoides Johnston 1835). 



Pl. 4, Figs. 29—35. 



Acrybia H. & A. Adams 1853. 



Shell with minute spiral strise and fine lines of growtli, covered by a light olive 

 brown or grayish cuticula; upper angle of the aperture acuminated; only a thin callus 

 (no pads) on the inner wall of the aperture. H. 12 — 35 mm A. flava (Gould 1840) 



(= ? Bulbus Smithii Brown 1838; = Natica aperta Loven 1846). 



Pl. 4, Figs. 20—28. 



Fam. Lamellariidae\ 



T. Vagina and bursa copulatrix- forming together a simple dilatation of the oviduct 

 with many adhering spermatocysts, Animal of separate sexes (gonochoristic). 

 Radula 1.1.1 (in the exotic Marseniopsis 2.1.1.1.2). Shell internal with 

 a very thin hyaline cuticula entirely covered by the secondary mantle; this with 

 an inspiratory canal in front margin but no expiratory canal on the right side (sub- 

 fam. Lamellariinse). 



A. Shell calcareous; whorls few but regularly continuous; peristome discontinuous, 

 columellar margin simple, not reflected Lamellaria Montagtj 1815 



(= Marsenia Leach 1820). 



B. Shell nearly wliolly corneous; last whorl in its hiiul part separated from the spire hy a slit (in the 

 place of the suture) Marseniella Bergh 1886. 



II. Bursa copulatrix^ a distinct sac protruding from the vagina; this with many ad- 

 hering spermatocysts. Animal hermaphrodite. Radula 2.1.1.1.2, the 

 lateral teeth with about 1 denticle on each side. Shell partly or wliolly internal, 

 calcareous with a very thin cuticula, with continuous peristome and reflected 

 columellar margin. Secondary mantle with an inspiratory canal in front mar- 

 gin and an expiratory one on the right side (subfam. Marsenininse ) 



Marsenina Gray 1850. 



III. Bursa copulatrix^ a distinct sac protruding from the vagina; this with or without 



one simple spermatocyst. Animal hermaphrodite. Radula 2.1.1.1.2, the 



lateral teeth bilaterally serrated. Shell internal or external, calcareous or coria- 



ceous, with or without a strong or feeble cuticula (subfam. Velutininse). 



^ The subdivision is based on the anatomical investigations of Marsenina, Velulina and Onchidiopsis, 

 published further on in the present work. 



^ »Schleim- und Eiweissdrtise» of Beruii 1880 — 87; cfr under Onehidiopsis further on. 



K. Sv. Vet. Akad. Handl. Band 50. N:o 5. 2 



