364 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vor. 48 
generic rank. The nuclear portion of the shell is analogous to 
that of Adelomelon, but the ovicapsule has not been described. 
The animal has been carefully figured by D’Orbigny. 
ZIDONA ANGULATA Swainson 
Voluta angulata Swainson, Exotic Conchology, 1, pl. mr and iv, 1821; 
SoweErzBy, Thes. Conch., Voluta, p. 202, pl. xivu, figs. 13, 14, 1847; 
Reeve, Conch. Iconica, Voluta, pl. xv, fig. 35, 1849. 
Voluta nasica SCHUBERT AND WAGNER, Suppl. bd. Conch. Cab., xu, p. 
10, pl. 217, figs. 3031, 3032, 1820. 
V oluta Dufresnei Donovan, Nat. Repos., 1, pl. 61, 1823. 
Volutella angulata D’OrBicnNy, Voy. Am. Mér., v, p. 423, pl. Lx, figs. 1-3, 
1841; Gray, Guide B. M., p. 35, 1857. 
V oluta angulata Woop, Index Test., Suppl., Voluta, no. 21, 1828; KiENER, 
Icon. Coq. Viv., Voluta, p. 65, pl. xxxvim, 1839; Tryon, Men., Iv, 
p. 98, pl. 20, figs. 112, 121, 1882; LAniLie, Rev. Mus. de la Plata, v1, 
p. 305 (extras, p. 15), pl. 1, figs. 5-8; pl. 1, figs. 69-78; pl. v1, and 
pl. rx, 1895. 
Voluta (Volutella) angulata Crosse, Journ, de Conch., xrx, p. 301, 1871; 
Tryon, Struct. Syst. Conch., 11, p. 164, 1883. 
Zidona angulata H. anp A. Apams, Gen. Rec. Moll., 1, p. 161, 1853; 
II, p. 618, 1858; FiscHer, Man. Conchyl., p. 605, 1883. 
Habitat—South American southeast coast from Rio Grande do 
Sul, Brazil, south to the Bay of San Blas, Patagonia; on sandy 
bottom, in comparatively shallow water. 
U.S: Nati, 25/402. 
Lahille has described varieties luteola, mixta (not V. nuxta 
Galeotti, 1837), similis, distincta, ventricosa (not V. ventricosa 
Dillwyn, 1817), and affinis (not V. affinis of Brocchi, 1814). The 
shell reaches to a diameter of five and a length of over seven inches. 
The apical spur of callus, found only in well developed specimens 
and frequently broken off, may attain over an inch in length beyond 
the apex of the spire. 
Recent explorations in Patagonian Tertiaries by Hatcher of the 
Princeton University Expedition, have been discussed by Ortmann, 
who has shown that the fossil species of that and the Chilean 
Tertiary have the nuclear characters of Adelomelon although there 
is a small group of species including one recent form, which from 
their sculpture I had previously suspected to be related to Plejona. - 
These forms are the nearest relatives of the typical Volutilithes 
which have yet been discovered on the American side of the Atlantic, 
but are also so closely akin to Adelomelon, that they can perhaps 
only be sectionally separated from it. These forms in Tertiary time 
extended their range to the west coast of South America, where, 
