20 solenid^:. 



(judging from a comparison of authentic specimens with 

 the descriptions of those authors) are varieties of S. 

 siliqua, and only distinguishable by the absence or size 

 of some of their teeth. The present species is the Hy- 

 pogaea crinita of Poli, S. gladius of Bolten, and S. gla- 

 diolus of Gray. 



C. Shell straight, tubular, and rather solid ; hinge at one end, 

 and only furnished with a single lateral tooth in each 

 valve. 



4. S. vagi'na*, Linne. 



S. vagina, Linn. S. N. p. 1113. 8. margmafus, F. & H. i. p. 242, pi. xiv. 

 f. I, and (animal, siphon only) pi. I. f. 3. 



Body cylindrical, pale yellowish-brown : mantle thickened : 

 tubes wrinkled across ; each is encircled "by several rows of brown- 

 ish spots, and near the extremity by a row of very short 

 tentacular cirri ; orifice of the lower tube distinctly scalloped, 

 that of the upper one plain : (/ills long, linear, orange-brown : 

 palps large, sharp-pointed : foot oblong, yellowish-white. 



Shell exactly cylindrical, and of equal size throughout, 

 somewhat glossy, opaque : sculpture as in the preceding two 

 species : colour pale yellowish-brown (with an orange tint in 

 aged specimens), and marked with streaks of a darker hue in 

 the transverse line of growth : epidermis membranous, yel- 

 lowish-brown : margins equally straight before and behind, 

 obliquely truncated at the anterior end, which is deeply con- 

 stricted (as if it had been tied while in a soft and plastic state 

 with a string), and transversely truncated or very slightly 

 curved at the posterior extremity ; dorsal area or compartment 

 not so distinct as in the other species : beaks inconspicuous, 

 separated by the constriction from the anterior end : ligament 

 very long and narrow, dark homcolour : hinge-line straight : 

 hinge-plate long, strengthened by a rib in each valve to support 

 the ligament, and thickened at the anterior end : teeth, in each 

 valve a single wedge-like cardinal, resembling in shape the 

 leaf of a water-lily, and attached to the hinge by an obliquely 

 twisted stalk ; the tooth hi the right valve is outermost : inside 



* A sheath. 



