NATURE OF EXCRETORY PROCESSES IN MARINE POLYZOA. 127 
Claparéde! in Bugulaavicularia, who describes them as 
“gelbe Tropfen” (p. 153), and states that they only occur 
in zoecia in which the polypide has degenerated. My own 
observations on the same species show that they are of normal 
occurrence in all the zoccia, and Claparéde’s failure to find 
them universally present was probably due to the fact that 
they are often colourless in the young zoecia. The yellow 
colour of these cells, so obvious in Claparéde’s figures, probably 
implies that they had taken up excretory pigments from other 
tissues during the degeneration of the polypide ; and Claparéde 
himself regards them as being excretory in nature. 
These cells are mentioned by various other authors, as by 
Joliet,2 who states that they are of very general occurrence in 
the Polyzoa. They are no doubt identical with some of the 
structures alluded to by Smitt® as “ Fettkroppar” or as 
‘floating cells,’ and are described by Cuénot* as “ amibo- 
cytes.” They are described by Prouho,® in the larva of 
Flustrella hispida, as very refringent aggregations of 
spherules, of a mulberry-like appearance, a description which 
I can confirm from my own observations. 
Most of the alimentary canal has a pale, diffuse, yellowish- 
brown colour; but the walls of the stomach and cecum contain 
numerous pigmented (brown) granules. A clear space, devoid 
of granules, always occurs at the base of the cecum, in the 
position shown in fig. 16, which, however, refers to the next 
species. 
1 “ Beitr. z. Anat. u. Entw. d. Seebryozoen,” ‘ Zeits. f. wiss. Zool.,’ xxi, 
1870, Taf. viii, figs. 1 B, 1C, ¢. 
2 L. Joliet, “ Cont. a ’ Hist. des Bryozoaires des Cotes de France,’ ‘ Arch. 
de Zool. Exp. et Gén.,’ t. vi, 1877, p. 233. 
3 F, A. Smitt, “Om Hafs-Bryozoernas Utveckl. och Fettkroppar,” ‘ Ofvers. 
af k. Vet.-Akad. Forh.,’ xxii, 1865 ; and in other places. 
4 L. Cuénot, “Et. sur le Sang,” &c., ‘ Arch. de Zool. Exp. et Gén.,’ 2e sér., 
t. vii, 1889; ‘ Notes et Revue,’ p. ILI. 
5 H. Prouho, “ Rech. sur la Larve de la Flustrella hispida,” ibid., 
Qe sér., t. vill, 1890, p. 427. 
