8 McMURRICH. [VoL. III. 
bases of the tentacles of the two inner cycles, towards which 
irregular white markings radiate from the white peristome. The 
tentacles are brown, ringed with connivent white bands. 
The base is adherent and slightly larger than the column, 
and is sufficiently thin to allow the attachment of the mesen- 
teries to shine through, giving rise to an appearance of white 
lines radiating from the centre to the periphery. In preserved 
specimens the base is always larger than the column, there being 
usually a strong constriction immediately above it. The limbus 
is usually more or less crenate. 
The column is cylindrical and exceedingly extensible. When 
fully extended it measures about 3.6 cm. (according to Lesueur 
5-7.5 cm.), with a diameter of 1.8 cm. About midway between 
the limbus and the margin it is provided with a series of cin- 
clides. Occasionally these are situated somewhat above the 
middle, and occasionally slightly below it, but never so low as 
to resemble the genus Adamsia. The arrangement of the cin- 
clides, which open on tubercles very evident in preserved speci- 
mens, is somewhat irregular. They are arranged in vertical 
series situated at regular intervals, but the number in each 
series varies. Occasionally each series consists of a pair, only 
one being placed immediately below the other, or the lower one 
may be slightly to the side, so as to appear almost as if alternate. 
Quite frequently three cinclides are to be found in each series, 
and in one form I counted as many as twelve in some of the 
series, the number in all of them being over three. This ir- 
regularity is prevalent throughout all the forms I have exam- 
ined, and a definite statement as to the number of horizontal 
rows in which the tubercles are arranged is impossible, since 
not only does the number in the various vertical series vary in 
different specimens, but even in the same individual while there 
may be six tubercles in one series, in the next there may be 
only one, and so on. 
The acontia are not emitted with as much readiness as in 
some other species of Azpfasza, and it is probably on this account 
that Lesueur failed to perceive and record their presence. I 
have seen them as white filaments protruded in considerable 
numbers through the cinclides. 
In none of the specimens that I examined were any signs of 
a sphincter muscle observed. It is noteworthy that in one 
