GASTEROPODA. 363 
radiating, greenish-brown coste, with the intervening sulci dark chest- 
nut; towards the apex a leaden colour prevails. Within deep shining 
brown, inclining to opalescent, margin distinctly crenulated, whitish, 
with the sulci showing through of a clear brown. ‘The strie are 
roughened by the intersection of the coarse, uneven lines of growth. 
Siphonal margin slightly projecting ; impression slight, but the mus- 
cular cicatrix is deeply impressed; on each side of the head and 
near the siphonal exit are three deep impressions across the muscular 
scar, and these are observable in all Siphonarie, indicating some 
peculiar arrangement of the muscle of attachment. 
Figure 464, profile view of the animal, with the shell; 464 a, foot of 
the animal; 464 6, detailed view of the head. 
SIPHONARIA LATERALIS (Couthouy MS.) 
Testa parva, fragilis, inequilateralis, perobliqua, oblongo-ovalis, olivacea, 
sursum fuscescens, costulis radiantibus ad viginti-quinque obtusis, no- 
dosis, subequalibus : intus hepatica ; cicatrice musculart inconspicua. 
Siphonaria lateralis (Cournouy MS.) Proceed. Boston Soc. Nat. 
Hist., ii. 153. August 1846. Expedition Shells, 11. 
Anima much smaller compared with the shell than that of S. Les- 
sont, being easily contained within it. Body and mantle of a dark 
olive-green. Siphonal fold paler and unusually small. Head rather 
small and scarcely emarginate in front; an indistinct black line sur- 
rounds the inferior face of the cephalic mass, and a reddish ring sur- 
rounds the mouth; remainder of the head dark slate-coloured, as is also 
the foot, except an ochreous border on the margin above. Hyes very 
small. [J. P. c.] 
SHELL small and thin, fragile, oblong-oval, diagonally very oblique, 
apex elevated, acutely prolonged and recurved, nearly posterior, and 
at the left side, which is nearly rectilinear and vertical, while the right 
side is gradually sloping and curvilinear, scarcely modified by a sipho- 
nal angle. Surface dusky brown, rather rough, and furrowed by about 
twenty-five slight, rounded, undulating ribs, roughened by small tu- 
