4 SIR C. ELIOT. 



organs themselves. Sars, who is quoted by some subsequent authorities, gives 

 (Mollusca Regionis Arcticse Norwegise, 1878, p. 328) maxillae nullae as a character 

 of Fain. Limacinidae, but on Plate XVI., 17, b, he figures a collection of lamellae with 

 denticulate or fringed edges, and explains them (p. 462) as maxilla una 190"* aucta. 

 But in fig. 21, b, of the same Plate, representing the buccal parts of Clione limacina, 

 what appears to be one of the hook sacks is described as maxilla una 15' es aucta. 

 It is clear therefore that he did not restrict the meaning of the term maxilla to the 

 ordinary molluscan jaw. 



Neither in Limacina antarctica nor in L. retroversa have I been able to isolate 

 any hard jaws, such as are frequently found in Opisthobranchiata, but sections show 

 that the sides of the cavity bear folds which are covered with a very thin chitinous 

 layer. 



LIMACINA ANTARCTICA, Woodward. 



See Pelseneer, ' Challenger ' Reports, Vol. XXIII. (1888), Thecosmata, p. 22 ; id., Voyage du 8. Y. 

 Belgica, Mollusques (1903), p. 29 ; Meisenheimer, ' Valdivia,' Pteropoden (1905), pp. 7, 8 ; id., Die 

 Arktischen Pteropoden (190C), pp. 409-413 ; id., Siidpolar Expedition, Pteropoden (1906), pp. 96-98.* 



The numerous specimens obtained by the Expedition differ considerably in size, 

 colour, and general appearance, and may be classified under three heads : 



(A.) Black and yellow specimens. The majority are about 3 mm. wide and 

 2 mm. or a little less in height, but four are as much as 5 5 mm. broad and rather 

 more than half as much in height. An operculum was often found. The fins, 

 hermaphrodite gland, and the majority of the organs are of a pale lemon yellow, 

 varying considerably in intensity, but contrasting markedly with the black mass 

 composed of the digestive organs, and especially of the liver. The shell is extremely 

 fragile and in bad condition, being not only considerably broken in nearly all 

 specimens, but also pierced by numerous holes. The word picric is written on some 

 of the labels, and probably all these specimens were killed with picric acid. This 

 has caused the fins and head parts to remain well expanded, but the action of the 

 acid has coloured the light portions yellow and partially destroyed the shells. 



Specimens of this class are recorded from : 



(1) Lat. 61 46' 8. ) Numerous . 

 Long. 140 12' E. 5 



(2) Lat. 61 40' 8 j Fftir] numerom 

 Long. 141 32' E. ) 



(3) McMurdo Bay . . . . 



(4) Lat. 66 52' 8. ) A fcw 

 Long. 178 15' E. 5 



(5) W. Q 



(6) Wood's Bay . 



* Full titles and references will be found at the end of the Memoir. 



