THE NAUTILUS. 95 
A specimen from Humacao, Porto Rico, which may be taken 
as type locality, is figured. It scarcely shows growth striae, but 
the oblique cuticular threads are very well developed, extend- 
ing upon the base. The umbilicus is contained between 10 and 
11 times in the diameter. Alt. 2.25, diam. 2.5 mm., umbil- 
icus 0.23 mm.; 44 whorls. 
The specimens from Florida (fig. 3, Fikahatchee Key) are 
often larger, diam. 3 to 3.2 mm., with the umbilicus slightly 
larger, 74 to 8 times in the diameter. The sculpture is rarely 
so perfectly developed (or preserved) as in the Porto Rico 
shells. It is a common species on the keys and in some places 
on the mainland, as at Miami and Osprey. 
A single small example from Brownsville, Texas, has the 
umbilicus remarkably small, contained about 14 times in the 
diameter. It is more depressed than T. cxcoides. It may rep- 
resent a distinct race, but further material is needed. 
Guppy has recorded the species (as Helix verensis) from Trin- 
idad. Specimens are at hand from St. Lucia (Tate), Cariaco, 
Venezuela (F. R. Cocking) and the U.S. of Colombia (R. Swift 
coll.). All of these are rather openly umbilicate, like the most 
widely umbilicate Florida shells, but not as open as T. 
fuscula. 
The late Mr. E. A. Smith, in his excellent paper on Trinidad 
shells (Journ. of Conch. VIII, p. 239), considered plagioptycha 
and ierensis synonyms of fuscula Ad., but while the difference 
is not great, I have been unable to trace a real transition in the 
size of the umbilicus, and for the present it seems best to recog- 
nize the distinction. I have seen but three Jamaican speci- 
mens, however. . 
THYSANOPHORA CHCOIDEs (Tate). Fig. 4. 
Helix cxcoides Tate, Amer. Journ. of Conch. V, p. 153, Feb., 
1870. 
Helix guatemalensis Crosse et Fischer, Journ. de Conchyl. XX, 
p. 222, 1872; X XI, p. 274, pl. 9, fig. 3, 1873; Miss. Sci. Mex., 
Moll., II, p. 664, pl. 71, figs. 9-95 (Guatemala, Sarg. ). 
Acanthinula granum Strebel, Beitrag Mex. IV, 18S0, p. 31, 
pl. 4, f. 13 (Plantage Mirador). 
Yucatan: Progreso (Heilprin Exped. 1890). Guatemala: 
