18 ANIMAL OF NASSA. 
F. § H. Foot broad, expanded, and angulated in front; behind, 
acute as in N. tenia, Gmel., Q. & G., ‘Voy. de l’Astrolabe,” pl. 32, 
f.13; blunt, asin N. Isabellei, D’Orb., ‘‘ Voy. dans l’Amerique,” pl. 61, 
f. 19 ; slightly notched as in N. incrassata, Miill. ; deeply nicked as 
in N. mutabilis, Linn.; bifurcate (each lobe divided into two) as in 
N. marginulata, Lam., var., “ Voy. la Bonite,” pl. 41., f.1; and lobes 
distant as in N. arcularia, Linn.; caudal filaments varying in 
length; branchial plumes two; animal of various colours, blotched, 
lined, and dotted with lighter and darker tints. 
The Nasse are very active, and not at all shy when kept in 
confinement. They may be seen occasionally floating with the foot 
upwards ; they feed on bivalves, the shells of which may be seen 
bored with circular holes; the shells of the Nassze themselves are 
often seen similarly perforated. ‘‘ N. reticulata is destructive to 
oysters, the shells of which are pierced by it.”—Zool. Record. Tf 
the small round holes found bored in bivalve shells are to 
be attributed to the ravages of these and kindred mollusks, very 
few genera escape their attacks, and I have seen shells from 
West Africa, Ceylon, Singapore, and the Philippines so pierced 
that almost every second mollusk must have been preyed upon. A 
curious instance of want of judgment on the part of one of the 
Mollusca is before me—a solid spine of an echinus has been par- 
tially bored. Two holes are sometimes bored in one shell, the 
enclosed animal having been able to elude the grasp by retiring out 
of reach of the first attempt; how it fared on the second trial I 
cannot say. - 
The spawn cases differ in the different varieties; in N. re- 
ticulata, Linn., they are deposited on different substances, and are 
arranged in closely imbricated rows, being small compressed 
pouches. “In N. incrassata, Miill., they are solitary, yellowish, and 
shaped like a round flask with a small neck or opening at the 
top.” —Jeff. They are found ranging from the littoral zone to 620 
fathoms, the N. brychia, Watson, “‘ Challenger” Expedition, having 
been obtained at this great depth. Some of the species have been 
observed to spring up and throw themselves over on being suddenly 
disturbed ; they glide along the surface of the mud, leaving a 
