S.A. NAT., VOL. XIV. 
May, 1933. By Bern ard C. Cotton (ind f. K. Godfrey. 93 
104 fathoms. Also Avest of Ifucla 80-300 fathoms measuring 17 
mm. X 13 mm. XvJincrous specimens. This species is witiiout 
appreciable lateral points. Localities — Atlantic, J^adtic and In- 
dian Oceans. 
Diacria Cray 1847. Shell tricuspidate, the terminal point 
long; Avith lateral slits opening into the cervical aperture. Type — 
llyalaea Irispivosa Lesueur 1821. 
D. trispinosa Lesueur 1821 {IJyalaea). ''d’hc Three-spined 
Diacria.” Depressed, straight, kite-shaped; anterior extremity, 
01 the portion above the acute lateral spines, Is much shorter than 
the posterior end; the latter produced into a very long and slen- 
der straight caudal spine; transparent Avhlte, brownish near the 
lips and at the commencement of the tail; mouth short, narroAv, 
semi-elliptic; marginal fissure extending to the lateral spines is 
linear; both lips abruptly reflected; upper and lower surfaces of 
shell nearly equally convex, mostly without marked concentric 
striae; upper surface projects semicircularly beyond the straight- 
ish labial edge of the loA\'cr; upper surface with a broad rounded 
central axial fold, generally divided in front into three smaller 
ones, flanked on each side Avith a strong narrower fold; lower 
surface Avith a slight fold adjacent to each lateral spine. Beach- 
port to Xeptune Islands, 90-300 fathoms. Xumerous specimens. 
Also \^’estcrn Australia, 80 miles Avest of Kucla, 80 fathoms, 
measuring 7 mm. x 6 mm. Localities — Atlantic, Indian, Pacific 
Oceans, and Alediterraucan. 
Clio Linne 1767. Clio, a daughter of (Jeeanus. Shell 
p\ ramidal, compressed at the sides, and ridged lengthwise, or 
spinous; mouth wide, angular. Ly[''e — L7D pyramidata Linne 
1767. Animal triangular, ending in a long spilke. Jeffreys, 
referring to tins genus, quotes from Shakespeare — “Brighter than 
glass, and }‘ct, as glass is, brittle.” Me further adds that Clio 
IS perhaps the only phosphorescent kind of Pieropod. 
C. pyramidata Linne 1767. PL I, fig. 18. ^'4’he Pyramidal 
Clio.” Triangular, convex in front, slightly concave on the back, 
abruptly sloping to a fine point, extremely thin and fragile, quite 
transparent, and lustrous; clear white; lengtliAvise ridges, live, 
in front, symmetricaL the outermost and largest, the central one 
Intermediate in vsize between those and the other tAvo; one ridge 
also at the back; dead shells exhibit numerous transverse and 
llexLious striae, especially on the -back; nucleus spearhead or 
sharply ovate, separated by a very narrow' line from the rest of 
the shell, mouth arched in the middle and sloping Avith a gentle 
curve to each side. Length 15, breadth 13.5 mm. Cape Jaffa, 
and 35 miles S.W. to Xeptune Islands, 90-300 fathoms. Alsc 
80 miles W. of Kucla, 80 fathoms. This species is reported as 
