12 SIR C. ELIOT. 
distortion. The following is an analysis of a radula of 32 rows, row No. 1. being 
the hindmost :— 
Rows 1-11 8 1 8, the median tooth being smaller ini than in i. 
Rows iii-ix . 8 0 8. 
Rowx . . 7x 0x7, where r indicates a rudimentary lateral." 
Rows xi—xiv [PVN 
Row xx . - 6r 0x76 3 : + " 
Rows xxi-xxvi. 6 0 6. 
Rows xxvi-xxx 5 09. 
Row xxx 3 a4t 20) 4: 
Row xxxil 3 0 3. 
The shape of the teeth is much as in Clione limacina, except that the median teeth 
(11gh) are markedly smaller and less distinctly cuspid, and that the laterals in the 
hindmost rows (1lef) have forked bases. It is noticeable that several specimens have 
been preserved in the act of holding and apparently eating small elongate fishes, 
which are still attached to them (fig. 12). 
In Cl. limacina the penis is large, frequently found exserted, and provided with 
a large accessory organ (vide Boas’s figure reproduced by Meisenheimer in Die 
Arktischen Pteropoden, p- 415); but these characters are not found in any of the 
present specimens of Cl. antarctica. The penis is small, invariably retracted, and no 
accessory organs were discovered. Too much stress should not be laid on this 
difference, for no doubt the accessory organs may have a very different appearance 
in the same species when exserted and when retracted. 
The presence of the larval rings and the small size of the penis naturally suggest 
that this form is immature, and it is also noticeable that the specimens were all captured 
between the months of November and March (though in different years), most of them 
in January and February. This certainly makes it probable that they are all in the 
same and possibly not adult stage of development. On the other hand, it is clear from 
a comparison of Arctic and Antarctic specimens of the same size that the young Clione 
limacina is not more like Cl. antarctica than are the full-grown individuals. Also 
the type specimens of Clione antarctica, captured by the ‘Southern Cross’ off 
Cape Adare and lent to me for examination by the kindness of Mr. E. A. Smith, 1s.0., 
resemble those found by the ‘Discovery’ in most external points except the 
colour, which is dirty green with purplish spots, a difference no doubt due to 
the method of preservation. The length is 20 mm. or a little less, the larval rings 
are more or less distinctly visible, the fins, foot, and buccal cones are as in my 
specimens. 
} The conformation of the radula may be due to one or both of two causes :—(a) In most opisthobranchs 
the front, that is the earliest rows of the radula, contain fewer teeth than the posterior or later rows. (6) As, in 
this case, the radula is split into two portions, it is possible that not only the central tooth, but the inner laterals 
on either side are worn away, in which case r would indicate a vestigial tooth. 
