244 SCAPHANDER. 



Genus SCAPHANDER Momfort, 1810. 



Scaphander MONTF., Conch. Syst. ii, p. 334. type S. lignarius. 

 Assula SCHUM., Essai, etc., p. 78, 258, type A. convoluta=B. lignar- 

 ia L. (1817). Gioeni GIOENI, Descriz. di ima nuova Fam. ediun 

 nuovo Gen. di Testacei, trovati nel littorale di Catania, p. xxv, (iii 

 to xxxiv), plate, figs, i-xiii, Naples, 1783 (Gizzard with plates, etc., 

 of S. lignarius}. Gicenia BRUG., Encycl. Meth. i. p. 502 (article 

 "char"). Tricla PHILIPSSON, Dissertatio Hist.-Nat, Nova Testa- 

 ceorum Genera, p. 8, Lund, 1788 (gizzard with plates). 



Shell entirely external, imperforate, ovate, rather solid, with the 

 vertex narrow, concave and closed by a callus over the spire ; aper- 

 ture as long as the shell, sinused behind, narrowed above, dilated 

 and effuse below ; columella long, simply concave, with reflexed, ap- 

 pressed edge. Type S. lignarius. 



Animal (pi. 32, fig. 24, S. lignarius} with a lar^e pentagonal or 

 hexagonal frontal disc, the posterior margin produced in two broad, 

 short subobsolete lobes; no eyes; foot about the length of the shell, 

 truncated behind ; lateral lobes large and well developed. Gizzard 

 (pi. 61 fig. 36 lateral view, fig. 37 dorsal view) armed with two 

 large flattened subtriangular plates (pi. 61, fig. S3, pi. 32, fig. 25) 

 and one lanceolate, laterally-compressed plate (pi. 61, figs. 34, 35). 

 Radula narrow and minute, tooth-formula 1*1' 1. The central teeth 

 are small, subquadrate, subobsolete, not denticulated. Lateral teeth 

 large, sickle-shaped (pi. 61, figs. 39, 40, S. lignarius}. 



The form of the shell is quite characteristic, but the main 

 peculiarities of the animal are anatomical. The dentition is alto- 

 gether peculiar, although showing much affinity to that of Diaphana 

 and Atys ; the external anatomy is most like Atys ; the gizzard 

 plates are characteristic, two being very large and subtriangular, 

 while the third is folded upon itself and of a narrow, lanceolate form, 

 fitting between the large ones. 



Not unnaturally, the gizzard with its plates has been described as 

 an independent genus, and two generic names have been applied to 

 it, both prior in date to Scaphander ; but Draparnaud in 1800 dis- 

 covered their true nature, and it was also known to Montfort. 



Besides the typical group of Scaphander, in which the parietal 

 wall of the aperture is smooth, a subgenus Sabatia has been institu- 

 ted by Bellardi, for forms in which there is a parietal entering 

 callous fold. These lead the way toward the genus Smatagdinella 



