380 Proceedings of the Royal Fliysical Society. 
the lobe ; cell tubular, without trumpet-shaped mouth ; cell 
and animal colourless/' Freya stylifer is the smallest spe- 
cies I have yet seen of the genus to which it belongs ; when 
contracted within its tube, it projects the curious style, 
which is doubtless a sense organ, beyond the opening, only 
entirely retracting it when rudely disturbed. 
During the last summer I had an opportunity of watching 
another species of Freya {F. producta) building up its re- 
markably constructed cell. The cell of this species, which 
is often immensely prolonged, is formed of a spiral ribbon 
of chitine, cemented by a thick internal layer of soft green 
sarcode, secreted by the body of the animal, so that the 
whole forms a hollow tubular spring, like the spiral wire 
tubes formerly employed for conveying gas to moveable 
burners. These tubes will therefore bend aside like a wil- 
low twig on any rude contact from the animals which are 
constantly dashing about, and will instantly regain their 
proper position. The young Freya "producta^ which is a free 
swimming larva, fixes itself, and secretes the lower part or 
body of the cell from the outer surface of its body ; it then 
begins to form the elongated neck by depositing the chitine 
and sarcode on the upper edge of the constantly lengthening 
ribbon, carefully moulding the plastic materials with its two 
short rotatory lobes, which it uses like a pair of hands (PL 
XIX. fig. 2), just as Sabella and Serpula mould their tubes 
with their hand-like secreting leaflets. Having built its 
tube to the requisite length, it finishes it off with a hand- 
some trumpet-shaped mouth, and then retires to develop its 
long rotatory lobes. Occasionally the animal outgrows its 
dwelling-place, and finds it necessary to lengthen its tube. 
For this purpose a large quantity of dark green matter is 
collected in the body of the animal, a little below the rota- 
tory organ (fig. 3 &) , and from this part chitine and sarcode 
are secreted, which are instantly moulded into shape by the 
rotatory lobes, and a new^ spiral tube rises up from within 
the trumpet-shaped mouth of the old one (fig. 3 a). 
5. Chcetospira maritima (n. sp,, T. S. W.) 
Two species of this remarkable animal have been noted by 
Lachmann — C. Mulleri and G. Mucicola. Chsetospira is de- 
fined as a Stentor, in which the ciliary spiral and the paren- 
