238 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Acteon (Microglyphis) estuarinus Datt, n. sp. 
Shell small, white, plump, with a very short, rather acute spire, and swollen 
last whorl; there are four and a half closely coiled whorls, the nucleus being sinis- 
tral and sunken; when fresh, the shell is of a translucent pinkish white, the 
thicker parts near the suture are more opaque and give the effect of a white band 
in front of the suture; the general form resembles that of 4. (M/.) curtulus, 
though the shell, with the same number of whorls, is much larger, the spire less 
evenly dome-like, and the nucleus more sunken; suture very distinct, almost chan- 
-nelled; sculpture of fine, close-set, minutely punctate spiral lines, hardly visible 
without a lens; aperture with a well-marked anterior sulcus or canal; anterior 
plait on the pillar strong, prominent, the posterior plait weaker, and ending fur- 
ther within the aperture, but quite distinct. A very thin wash of callus on the 
body; outer lip thin, simple. Alt., 5.5; diam., 3.7; spire above the last whorl, 
1.0 mm. 
U. S. S. “ Albatross,” station 3194, off Estero Bay, California (N. Lat. 35° 
23’ 30’), in 92 fathoms sand, bottom temperature 45°.9 F. 
It may be accidental, but two living specimens were both without the opercu- 
lum, which is present in the littoral species of Acteon. The species of Microgly- 
phis at present known are: 
M. estuarinus Dall, off Estero Bay, Cal., in 92 fms. 
M. breviculus Dall,! “ Sta. Rosa Id., Cal., ss 53 
M. mazatlanicus Dall, ‘ Mazatlan, Mexico, ig 995 “ 
M. perconicus Dall, “Galapagos Ids., SOILED ates 
M. curtulus Dall, «Magellan Strait Sine peo as 
. The temperature of the water in which they lived was 37° to 48° F., and the 
bottom either sandy or muddy. 
Scaphandridae. 
SCAPHANDER MonrTrort. 
Scaphander Montfort, Conch. Syst., 1810, 2, p. 334, type Bulla lignaria Linné. 
Assula Schumacher, Essai, 1817, pp. 78, 258. 
The species of this genus are readily recognized, but the smaller forms belong- 
ing to the family are often so similar to Acteocina (Gray, 1847, type Actaeon 
wetherilli Lea, better known as Tornatina A. Adams, 1850) that in the absence 
of the soft parts the reference of the shell to a particular group must be regarded 
as merely provisional. 
The nomenclature of the groups is also in an uncertain state, its final arrange- 
ment depending upon the anatomical characters as yet unknown. If we must 
1 See Plate 15, figure 12. 
SS 
