214 "TERRA NOVA" EXPEDITION. 



ordinarily attenuated appearance compared with the other specimens. The radula, 

 however, in both forms agreed with these of other hauls. 



Distrilnttion. Antarctic waters to 46 S. in the Pacific, and to about 50 S. in the 

 Indian Ocean (Meisenheimer, 1905). 



9. Cleodora coinpressa, Souleyet. 



Cleodora compressa, Souleyet, 1852 ; Boas, 1886 ; A. Vayssiere, 1913 and 1915. 



N.E. of Eio de Janeiro. New Zealand (off N. end of). 



Station 47, two. Station 86, seven. 



Atlantic (Equator). 

 Station 58, three. 



92, one. 



93, forty-eight. 



61, (?)one. 110, five. 



New Zealand (off N. end of). 

 Station 80, two. 

 ,, 85, eight. 



Only the examples from Station 93 possess shells. The specimen to which a 

 query is affixed is in bad condition and about 1 mm. in length. Pfeffer, Pelseneer, 

 Tesch and Bonnevie have considered this to be a young form of Ciirnliniu (J')i<i<-ria) 

 trispinosa. Specimens in the present collection, when compared with examples of 

 D. trispinosa, present such a very different appearance to the latter species that I have 

 had no difficulty in taking Vayssiere's view. Like him I have found that the younger 

 specimens are proportionately more elongate in form than older examples. Adult 

 shells of D, trispinosa measuring 10mm. in length by 7mm. in breadth represent very 

 average measurements for this species. If C. <;nnpressa were only a young form of 

 D. trispinosa it would seem very strange that it should still be only at the C. compressa 

 stage when the shell measures from 8-12 mm. in length by 4-5 mm. in breadth 

 (Vayssiere, 1915, p. 81). About 2mm. of the breadth given above of an adult shell of 

 D. trispinosa is occupied by the lateral " thorns," of which ( '. i-miipn'sxa never exhibits 

 any trace. In ( '. cuiii/in^sa the apron is only about half the height of the fins and has 

 a straight border. In D. trispinosa the apron extends above the fins and the free 

 edge takes a semi-circular sweep. The presence of gills in the lateral cavity, two 

 lateral appendages, a well-developed apron and a much reduced cephalic lobe are 

 characters of the genus Cavolinia, whilst the genus Cfi'm/ura possesses a very distinct 

 cephalic lobe, a small apron, and no gills or lateral appendages. The present examples 

 have a distinct cephalic lobe and no trace of gills. The only lateral appendages are 

 the up-turned peaks at the sides of the mantle-border. 



Distribution. Atlantic to about 39 N. (Vayssiere, 1915). Pacific (Boas, 1886). 

 It is difficult to give more exact geographical limits on account of so many authors 

 having considered this to be D. trispinosa. It did not occur in any of the hauls made 



