NWTCRAL HISTORY .SOClErY. 



150 



lievohing lines, lines on a univalve 



shell parallel with the whorls and 



suture (Fig. 34). 

 Rhombic, having four equal sides and 



oblique angles. 

 .Rhomboid, a figure of four sides, the 



opposite sides equal and parallel, 



but two of the sides longer than 



the other two. 

 Fibbed, with raised parallel ridges or 



lines. 

 Rimate, with a slight crack or chink, 



as the umbilicus of univalves when 



not fully open. 

 Rostrated, having a rostrum or beak 



with the mouth at the end. 

 Rostrum, the proboscis of univalves 



with the mouth at the extremity. 

 Rotund, rounded or spherical. 

 Rub'ginose, with a rough surface. 

 Rufous, of a brownish red color. 

 Rugose, rough with wrinkles. 



Series, a number of marks arranged 

 in regular order. 



Serrated, notched at the edge like a 

 saw. 



Sessile, without a stem. 



Setaceous, hiwing the slender form of a 

 bristle or covered with bristles. 



Shouldered, having a projecting ridge, 

 as the whorls of manv univalves 

 (Figs. 36 and 37). 



Simple, without break or notch, as the 

 peristome when continuing all 

 around ; and the pallia! line when 

 without notch or sinus (Fig. 3, H). 



Sinistral, left-handed, as the shells of 

 univalves which, when held so that 

 the apex is upward and the aper- 

 ture towards the person, the aper- 

 ture is on the left (Figs. 21 and 55). 



Sinuous, having the edge alternately 

 curved inward and outward (Fig. 



.1'^'^^' . . . \ 



Sinus, the notch in the pallial tine of 



many bivalves, showing the posi- 

 tion of the siphon (Figs. 7 and 9, 1). 



Siphon, the one or two tubes of mol- 

 lusks through which the water flows 

 to supply the animal with oxygen, 

 and, in bivalves, with food also 

 (Fig. 11, p, and Fig. 45, T>\. 



Solid, applied to shells which are 

 thick and strong. 



Spatulate, of the form of a spatula 

 used by druggists to pulverize sub- 

 stances. 



Spiculose, covered with sharp, hard 



points. 

 Spiral, windhig around, ys the whorls 



of the spire of most univalves. 

 Stfice, minute lines, but visible to the 



unaided eye. 

 Striate, covered with stria^, usually 



lines of growth. 

 Subulate, narrow and tapering to & 



sharp point ; awl-shaped. 

 Sulcate, marked with furrows or deep 



grooves. 

 Sulcus, a deep groove. 

 Superficial, just on the surface. 

 Superior angle, the upper angle. 

 Suture, the groove between the whorls 



of the spire of univalves (Fig. 32,- 



H). 



T 

 Teeth, in bivalves the term is used for 

 the cardinal teeth of the hinge (Fig. 

 3, C). 

 Tentacles, the projecting feeler-like 

 parts on the heads of snails (Fig. 

 45, C) ; and the long arms of squids 

 (Fig. 66). 

 Terete, cylindrical, but tapering like 



a twig of a tree. 

 Testaceous, shell like. 

 Tcofh'd hinge, a hinge with cardinal 



teeth, as most bivalves. 

 Translucent, nearly but not quite 



transparent. 

 Transverse, when elongated in a direc- 

 tion not usual, as when the aper- 

 ture is wider than long ; also ap- 

 plied to cardinal teeth when they 

 are longer in the direction of th« 

 length of the shell. 

 Trapezoidal, having four sides but the 



opposite sides not parallel. 

 Trilobate, with three rounded lobes 

 Truncated, having the end not round- 

 ed but square as though cut off. 

 I Tuberculate, covered with projecting, 



rounded points (Fig. 36).- 

 i TubereuUform, having the form of a 

 j tuber, like the white potato. 

 j Tubercles, rounded points or pimples. 

 I Tumid, swollen. 

 I Turbinate, shaped like a top. 

 ] Turreted, shaped like a tower (Fig. 

 1 55). 

 Turriculate, with the form of a tower. 



U 



Umlilieus, a depression or opening in 

 the centre of the base of many uni- 

 valve shells (Fig. 38, A). 



