Ampulliiui.] GASTROPODA. 293 



3. Ampullina apora, Watson, 1881. 



Natica (Amauropsis) apora, Watson, J.L.S., xv, 1881, 265 ; Chall. Rep., 

 xv, 454, p. 27, f. 11. Amaura apora, Wats., Index, 80. 



Shell conical-oval, thin, umbilicated, with a coarse brown epi- 

 dermis and a channelled suture. 



Diameter, 16-25 mm. ; height, 18 mm. 



Hob. The type is from the Arron Islands, in 800 fathoms. 



There is a species of Natica from Chall. Stat. 169, north-east from 

 New Zealand, 700 fathoms, which may perhaps be this species, but 

 it is in too bad condition for identification. (Watson.) 



Fam. LAMELLARIID^, d'Orbigny. 



Animal having a short muzzle ; tentacles subulate, with the eyes 

 at their exterior bases ; foot lanceolate, simple, without a cephalic 

 disc. The mantle gradually grows over the shell until the latter be- 

 comes, in some of the genera, completely internal. Intromittant organ 

 falcate, on the right side of the body ; there are 2 unequal branchiae. 

 Jaws are present. The radula has the formula 2+1+1+1 + 2 or 

 1+1 + 1. 



Shell thin, more or less internal, sometimes reduced to a non- 

 spiral lamella, generally spiral, with a short lateral and paucispiral 

 spire ; aperture large, entire, oval. No operculum. 



The Lamellariidce are carnivorous, living upon Hydrozoa, Alcyonaria, 

 and compound Ascidice. The eggs are deposited in the midst of 

 colonies of the latter. The first embryonic shell is uautiloid, with 

 spiral ridges ; the second is more simple, resembling a Carinaria. 

 These shells are united at their margins by a thin membrane. The 

 pelagic larval forms have received the names of Brownia, Echinospiia, 

 Cakarella, and Jasonilla. 



Genus 1. LAMELLARIA. Montagu (pars), 1815. 



Lamellaria, Mtg., Trans. Linn. Soc., xi, 1815, 11. Type: L. perspicua, L. 

 Coriocella, Blainville, 1824. Cryptothyra, Menke, 1830. Marsenia, Leach, 

 1847. Chelinotus, Swainson, 1840. Cryptocella, H. and A. Adams, 1853. 

 Ermea, Gray, 1857. 



Animal much larger than the shell, which is entirely concealed 

 beneath the dorsal shield ; shield thick, verrucose, notched in front ; 

 foot elongated, truncated anteriorly, acuminated behind ; eyes at 

 the outer bases of the tentacles. Dentition 1+1+1, the central 

 tooth subtrigonal, with the free margin denticulated and base in- 

 curved ; laterals large, the summit lanceolate, the margins denti- 

 culate ; no marginals. 



Shell internal, ear-shaped, thin, pellucid ; spire lateral, very small ; 

 aperture large, patulous, both lips regularly arcuated ; axis imper- 

 f orate. 



There are between twenty and thirty living species Atlantic, 

 Indian, and Pacific Oceans. 



