236 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Solidula (sp.) Fischer, Mus. Demidoff, 1807, p. 226; Tabl. Synopt. Zoogn., 1808, 
p. 126; type Voluta solidula Linné. 
Tornatelle Lamarck, Extr. du Cours de Zool., 1812, p. 117; not latinized, no species 
cited. 
Tornatella Lamarck, An. s. Vert., 1822, 6, p. 219. 
Speo Risso, Hist. Nat. Eur. Mérid., 1825, p. 235; type S. bifasciatus Risso, 1. ec. fig. 
107. 
Actaeon Voigt, in Cuvier, Das Thierr., 1834, 3, p. 201, not of Oken, 1815; Meek, 
Amer. Journ. Sci., 1868, ser. 2, 35, p. 87; and the majority of authors. 
Kanilla Sowerby, Edin. New Phil. Journ., 1835, 15, p. 367, nomen nudum. 
As Montfort says nothing to connect his dcteon with the mythological proper 
name Actacon, their identity is a pure assumption, and I therefore return to the 
original mode of spelling used by Montfort, Cuvier, D’Orbigny, Agassiz, and 
others of the earlier writers who adopted it. 
The genus is represented on the west coast of America in the recent fauna by 
the following groups : 
Acteon s. s. Spire produced, outer lip simple not thickened, a single plait upon the 
pillar, continuous with the anterior margin of the aperture and with no sulcus 
or canal anteriorly. Type A. tornatilis Gmel. 
Rictaxis Dall, 1871 (Actaeonidea Gabb, 1878). Like Acteon, but with the anterior 
end of the pillar truncate and projecting. Both the above operculate. Type 
A. punctocoelata Carpenter. ; 
Microglyphis Dall, 1902. Shell short and swollen, pillar with two distinct plaits 
and a well-marked siphonal sulcus anteriorily. Inoperculate. Type A. 
curtulus Dall. 
This last group resembles Zorzatellaea (bella) Conrad, 1860, described from 
the so-called “‘ Lignitic”’ of Alabama, but the latter differs by its thickened and, 
in the mature condition, denticulate outer lip, and peculiar acute nepionic shell 
which is quite unlike that of any recent form of Acteon known to me. Conrad’s 
original figure was taken from an immature specimen. ‘Tornatellaea is not known 
in the recent state. M.Cossmann has brought together indications of a large 
number of forms belonging to this family, but, unfortunately, the photographic 
figures by which they are illustrated are so imperfect that it is in many cases quite 
impracticable to gain from them any idea of the exact characters of the specimen 
figured. 
Acteon panamensis Datt, n. sp. 
Plate 11, figure 6. 
Shell with the apex badly eroded, but apparently blunt, with about four whorls, 
the last much the largest; spire shorter than the aperture; suture strongly 
marked, the whorl in front of it abrupt, but not channelled; periostracum pale 
