PTEROPODA. 13 
These specimens found by the ‘ Discovery’ seem referable to Cl. antarctica, E. A. 
Smith (/.c.). They can hardly be identified with Cl. longicaudata, Cl. flavescens or 
Cl. punctata, because those species, though imperfectly known, are said to have only one 
or two, and not three pairs of buccal cones. In my opinion they are also specifically 
distinguishable trom Clione limacina, though the species are, no doubt, nearly allied. 
The superficial difference in appearance is striking, and the divergent characters of the 
two species may be tabulated as follows :— 
CLIONE ANTARCTICA. CLIONE LIMACINA. 
1. The part of the body behind the fins is shorter 1. A specimen 18 mm. long consists of 2°5 mm. 
than in the Arctic form. A specimen 18 mm. 
long consists of 6 mm. head and fins + 
12 mm. body. 
There is a distinct neck behind the fins. 
. Considerably smaller than the Arctic form. Few 
individuals exceed 20 mm., even when arti- 
ficially extended. E. A. Smith gives 22 mm. 
as the length ; presumably the maximum of 
his specimens. 
. The integuments are thicker, firmer, and less 
transparent than in the Arctic form. In 
most specimens they are plentifully be- 
sprinkled with opaque yellow spots, some- 
times a little raised. 
doubtful, though not disproved. 
. The visceral mass extends backwards almost 
into the posterior third of the body. 
head and fins + 15°5 body. 
The broadest part of the body is just behind 
the fins, and as far as there is a neck it is 
between or above the fins. 
. Specimens 40-45 mm. in length are frequent. 
. The integuments are thin and _ transparent. 
Though spots are present they are not con- 
spicuous, and as a rule can only be seen when 
carefully sought for. The whole animal is 
flabby, and almost gelatinous. 
. Three, or at least two, larval rings are habitually 4. No larval rings found in individuals measuring 
present in individuals measuring 15 mm. or as much as 10 mm. When traces of the 
more in length. posterior ring are found in small specimens it 
is not shaped as in Clione antarctica. 
. The base of attachment for the anterior lobes 5. The base of attachment for the anterior lobes is 
of the foot is a narrow band. The posterior broad. 
lobe is larger and stouter in proportion to the 
anterior lobes than it is in Clione limacina. 
. There is an interval between the dorsal cone 6. The cones are equidistant. The dorsal is the 
and the other two. The median cone is the largest and the ventral smallest. 
largest. 
. Median tooth very small, and present only in 7. Median tooth larger, and present in all or most 
hindmost rows of radula. Laterals in hind- rows. Laterals with forked bases not found. 
most rows have forked bases. The number The number of laterals does not increase so 
of laterals gradually increases from 3 to 8, markedly, and the rudimentary teeth are 
the innermost teeth of the half row being found at the outer ends of the rows. 
sometimes rudimentary. 
. Penis small, and presence of accessory organ 8. Penis proportionately much larger, and provided 
with a large accessory organ. 
. The visceral mass is more compact and rounded, 
extending only a little way behind the fins. 
