PTEROPODA. 3 
(B.) Whitish specimens. In these the prevalent coloration is white or grey, 
the black visceral mass being seen more or less distinctly, according to the 
transparency of the shell. The animals are not much expanded, the fins being 
usually retracted, but the shells are better preserved than in the black and yellow 
specimens, being thicker, more opaque, less broken and less perforated. The breadth 
is about 3 mm. and the height about 1°75. These specimens were probably put 
straight into alcohol, which accounts for the contracted state of the soft parts and 
good preservation of the shell. They are recorded from :— 
CO AWELOEE s. 2 : : . Fairly numerous. 
(2) McMurdo Bay . : : . A few. 
(C.) These specimens, which are extremely numerous, are distinguished by 
(a) their small size, the diameter being usually about 1°50 mm., and few whorls ; 
and (b) the position of the fins, which form a sort of hood extending beyond the 
anterior part of the body. As this hood often bears fragments of shell, the whole 
animal sometimes bears a resemblance to Limacina inflata, as figured by Souleyet. 
But a comparison with specimens of that form, kindly lent me by Mr. E. A. Smith, 1s.0o., 
shows that the resemblance is merely superficial, and that there is no true rostrum 
above the hood. The coloration is varying: pure yellow, black and yellow, white, 
erey, and dark grey being all found. Some of the animals have been treated with 
picric acid, and some apparently put straight into alcohol or formol. The majority 
of the shells are poorly preserved, though in so large a mass of material good 
specimens were not wanting. An operculum is generally present; otherwise this 
form resembles those described above as A and B, and may be regarded as a 
younger stage. 
The Expedition brought back twenty-three tubes containing specimens of this 
type, all captured at Winter Quarters, none being recorded from elsewhere. 
Taking all the specimens together, I have little doubt that they represent a 
single species which may be thus described. 
The shell is between 5 and 6 mm. broad in large individuals, but considerably 
smaller in the majority, and the height is about half the breadth or rather less. In 
the best specimens it is white, imperfectly transparent, and faintly but distinctly 
striated, but the action of the preserving fluid often renders it extremely fragile 
and the striation may disappear. There are 3-6 whorls (5-6 in large specimens) 
divided by distinct sutures. The last whorl is considerably dilated and terminates 
in a large rounded lip, which is generally broken. The spire is somewhat flattened. 
The umbilicus is moderately wide and deep, but is not surrounded by any raised keel 
or special border. 
In large specimens the fins (fig. 1b) are about 4 mm. long and 3 mm. broad 
across the tips. They are shaped much as in Z. helicina and bear a small accessory 
lobe. The right tentacle is well developed, the left rudimentary. The foot is ample 
