MOLLUSCA OF PORTO RIOO. 
397 
Mitra straminea A. Adams. 
Milra straminea A. Adams, P. Z. S., p. 332, 1851. 
Mitra straminea Tryon, Man., iv, p. 140, pi. xli, fig. 188, 1882. 
Shell small, slender, with about eight somewhat rounded whorls, which are sculptured by strong, 
sharp revolving ridges; there are four or five of these on the upper whorls and fourteen to sixteen on 
body whorl; between the revolving ridges the surface is sculptured with sharp, longitudinal threads; 
aperture elongated, scarcely wider below; columella three-plaited. Color yellowish white. 
Length, 15; diameter, 5 mm. 
Mayaguez, Porto Rico, three worn and broken young shells. 
Mitra microzonias Lamarck. 
Mitra microsomias Lamarck, Ail. sans Vert., vil, p. 320, 1822. 
Mitra microzonias Tryon, Man., iv, p. 183, pi. liv, figs. 668, 569, 1882. 
San Juan, Porto Rico (Gundlach); West Indian region. 
Genus MITROMORPHA A. Adams, 1865. 
Shell small, somewhat elongate and biconic, with a globose nucleus; aperture scarcely or not at 
all notched behind; columella nearly straight, generally having faint vestiges of oblique plaits, which 
do not extend far into the shell; surface sculptured. 
Mitromorpha biplicata Dali. 
Mitromorpha biplicata Dali, Blake Report, ii, p. 165, pi. xxxv, fig. 1, 1889. 
Shell biconic, cancellated, yellowish or whitish, with brown flammules; nucleus glassy, of one 
and a half turns, other whorls five or six, slightly rounded; aperture not widened below; columella 
with two fairly strong plaits; outer lip lirate within. 
Length, 7; diameter, 3 mm. 
A fragment having a perfect aperture was- found at Mayaguez. 
Family FASCIOLARIlDrE. 
Genus FASCIOLARIA Lamarck, 1801. 
Shell imperforate, fusiform, solid; spire rather elevated, sharp pointed; aperture oval-oblong, 
with a canal in front; outer lip simple, furnished with lirse internally; columella concave, having a 
few oblique plications at its base. Operculum oval, pointed at the summit; its nucleus apical. 
Fasciolaria gigantea Kiener. 
Fasciolaria gigantea Kiener, Coq. Viv., Fasciolaria , p. 5, pis. x, xi, 1840. 
Shell very large, solid, fusiform, with about ten whorls; spire well elevated, pointed; growth 
lines strong and irregular; the surface is covered with a series of more or less strongly developed, 
rounded, revolving ribs, and between these there are fainter ones; near the center of the whorls there 
is a row of large nodules, which are somewhat distantly spaced and which fade out on the body 
whorl; aperture ovate-oblong, the outer lip more or less ridged within; canal long, open, and slightly 
recurved; columella incurved, furnished with three folds below. The surface is salmon or chamois 
colored, and is covered with a strong, reddish-brown epidermis, which cracks and peels off when the 
shell is dry. The aperture varies from dirty straw color to deep salmon or reddish. Animal deep red. 
Length, 16 inches to 2 feet; diameter, 7 to 10 inches. 
Mayaguez, Porto Rico, one very young shell. 
This is one of the largest of the Gastropods, being excelled in size only by the Megalatractus 
aruanus of Australia. The species varies much in the development of the tubercles, in some cases 
being almost destitute of them, and in others they are very strong and scarcely diminish in size on 
the last whorl. It is abundant in the waters of the Southeastern States, and differs from the F. princeps 
of the Pacific coast by the smooth external surface of its operculum. 
Fasciolaria tulipa Linnaeus. 
Murex tulipa Linnaeus, Syst. Nat., ed. x, p. 754, 1758. 
Fasciolaria tulipa Kiener, Coq. Viv., Fasciolaria, p. 2, pis. I, n, 1840. 
Shell with about nine somewhat rounded whorls, with a deep, well-defined suture, with irregular, 
impressed growth lines and revolving sculpture. This sculpture may consist of rather sharp, close 
