REPOET ON THE PTEROPODA. 
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Subgenus Clio, Linne. 
1767. Clio, Linne, Systema Naturae, ed. 12, p. 1094 ( non Muller, 1776). 
1810. Cleodora, Peron et Lesueur, Histoire de la Famille des Mollusques Pteropodes, Ann. 
Mus. Hist. Nat. Paris, t. xv. p. 66. 
1829. Balantium, Anonymous (Children, fide Gray), Journ. Roy. Inst., vol. xv. p. 220. 
Characters and Description. — Shell, of a somewhat angular form, colourless, 
compressed dorso-ventrally, with lateral keels. An anterior transverse section is thus 
always angular laterally. There is generally a crest or rib extending longitudinally along 
the back, and usually projecting. The embryonic shell varies in form, but is always 
definitely separate from the rest. 
Animal. — The aperture of the mantle is smaller than the aperture of the shell ; the 
margins are laterally united for a certain distance, as in Cavolinia ; the simple lateral 
prolongations of the mantle corresponding to the lateral keels hardly extend beyond the 
margin of the shell ; the fin has a non-muscular space situated towards the middle of the 
distal margin ; the left tentacle is always distinctly visible ; there is a triangular dorsal 
lobe between the two fins, and formed by the union of the two lips ; the anus is situated 
far in front, near the aperture of the mantle. 
Key to the Species. 
I. Shell with lateral keels over its entire length. 
1. Shell with dorsal ribs very slightly projecting. 
A. Shell with a broad posterior portion, .... 
B. Shell with a narrow posterior portion, .... 
2. Shell with dorsal ribs markedly projecting. 
A. Shell with three dorsal ribs, ...... 
B. Shell with five dorsal ribs, ...... 
II. Shell with no lateral keels on the posterior portion. 
1. Shell without lateral spines. 
A. Shell with the lateral margins almost parallel, .... 
B. Shell with the lateral margins very divergent. 
a. Transverse grooves on the posterior portion, dorsal ribsjnultiple, . 
b. No posterior transverse grooves, the dorsal ribs undivided, 
2. Shell with lateral spines, ....... 
Clio andrese. 
Clio polita. 
Clio balantium. 
Clio chaptali. 
Clio australis. 
Clio sulcata. 
Clio pyramidata. 
Clio cuspidata. 
7. Clio andrese (Boas). 
1886. Cleodora andrese, Boas, Spolia atlautica, p. 80, pi. i. fig. 1 , pi. ii. fig. 12. 
This species, which closely resembles Clio polita (see below), is distinguished by its 
greater breadth, especially in the posterior portion, by its two equally bulging faces, 
by its more marked flattening, by its curvature, especially localised on the posterior 
