380 Proceedings of the Royal Physical Society. 



the lobe ; cell tubular, without trumpet-shaped mouth ; cell 

 and animal colourless." Freya sty lifer 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 (PI. 

 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 b), 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 maritirna (n. sp., T. S. W.) 



Two species of this remarkable animal have been noted by 

 Lachmann — C. Mulleri and C. Mucicola. Cheetospira is de- 

 fined as a Stentor, in which the ciliary spiral and the paren- 



