190 MACROSCHISMA. 



in a sloping direction obliquely upwards on the fore part of the body. 

 The tentacles are filiform and very long ; and the eyes large, black, 

 and conspicuous, are on slight swellings at their outer bases. The 

 front edge of the mantle is extended, and gives the appearance of a 

 large veil over the head. The mantle is not developed, nor does it 

 cover the shell as in some members of the Fissurellidce, and neither 

 the mantle margin nor the anal tube is fringed. The edge of the 

 mantle is furnished with short papillae, four on each side and two 

 behind, which are recurved over the edge of the shell. The anal 

 tube is elongate and cylindrical, and is directed backwards and a 

 little upwards through the foramen in the shell. The foot, large 

 and fleshy, is produced behind and tapers to a point. It is ovate in 

 outline, and the sides are simple, and not furnished with cirri or 

 papillae. 



In progression the form of the foot varies considerably, sometimes 

 being greatly dilated at the sides, and at others extended in front 

 and contracted and pointed behind. The tentacles are red ; the 

 eyes black with a light areola ; the body is light brown, lineated 

 with darker brown. 



Species. 



M. SINENSIS A. Adams. PI. 59, figs. 56, 57, 58, 59. 



Shell oblong, the length a little exceeding twice the width, 

 elevated, the altitude about one-fourth the length. Lateral margins 

 a trifle convex, subparallel. Surface seen under a lens to be all over 

 exquisitely latticed by clear-cut radiating and concentric striae. 

 Perforation narrow, long, somewhat wider posteriorly, about one- 

 third the length of the shell. Color grayish-white, with one or two 

 broad radiating brown bands on each side. 



The peristome in this species is curved upward both in front and 

 behind, but decidedly more so in the rear. The outline is quite 

 blunt at the ends, especially posteriorly. The color of adults is a 

 dull whitish, with a broad brownish ray extending toward each 

 corner of the shell, the posterior pair arising from about the middle 

 of the perforation. This fissure is very narrow, its greatest breadth 

 scarcely a*fourth of its length ; it is scarcely dilated posteriorly, but 

 as in the other species the margin is excavated there. Inside whit- 



