ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
77 
found to be glycogen stored in certain cells of the peritoneal epithelium ; 
in Phreorycies it is replaced by fat. (2) The elements of the coelomic 
fluid. These consist of varying stages in the development of amoebo- 
cytes, and in rare cases, e.g. Allolobophora rosea , also of motionless 
elseocytes. This worm exhibits in addition the remarkable mucocytes 
of Rosa, which are ejected by the dorsal pores. The red blood also 
contains amcebocytes. (3) As to the function of the dorsal pores, Cuenot 
is inclined to regard the occasional ejection of the ccelomic fluid through 
them as a protection against desiccation ; they may also be excretory. 
(4) Phagocytosis is important and well marked. By means of it waste 
substances and degenerating cells are eliminated, and the organism is 
protected against the action of parasites. The following cells act as 
phagocytes : the young amoebocytes of the coelomic fluid, the special 
phagocyte cells of Perichseta , and certain cells of the nephridia. (5) The 
process of excretion in the Lumbricidee is carried on by five different 
sets of cells: — («) The cells of the nephridia, ( b ) the chloragogenous 
cells of the intestine, (c) the peculiar “ bacteroidal ” cells of the connec- 
tive tissue, ( d ) the yellow cells, (e) the amoebocytes of the red blood. In 
addition the amoebocytes of the coelomic fluid are important in trans- 
porting to the nephridia, skin, &c., the products of the chloragogenous 
cells. 
Regeneration in the Naidse.* — Herr Paul Hepke has studied histo- 
logically the origin of new organs in species of Nais which have had 
portions of the body amputated. The results serve to emphasise the 
great importance of the ectoderm in the regenerative processes. The 
epidermis speedily closes over the wound, and forms a many-layered cap of 
ectoderm cells from which all the organs ultimately take origin. Thus 
the gut originates as a bud of ectoderm growing in towards the old gut. 
This acquires a lumen, and becomes stomodseum or proctodaeum as the 
case may be. The mesoderm originates from ectoderm cells which arise 
at either side of the Anlage of the gut, and go free into the body-cavity. 
In general there seems to be a return to the period of the origin of the 
germ-layers, the cells exhibiting their primitive marvellous power of 
differentiation. 
Budding of Chaetogaster.j — Herr Max von Boch’s paper on this 
subject affords an interesting comparison with that of Hepke. He found 
specimens of Chsetogaster diaphanus Truith., which, as already described 
by Semper, formed long chains of zooids. The budding occurs at some 
distance from the posterior end of the last worm. Here a proliferating 
zone forms a new tail in front, a new head behind, so that two complete 
zooids arise from the originally single one. After a period of growth the 
process is again repeated. Sections show that at each side of the body 
there are gaps in the muscular coat, occurring between dorsal and lateral 
muscles and ventral and lateral muscles respectively. At these gaps 
the ectoderm grows into the body-cavity, and the four patches unite with 
one another and with certain cells budded off from the ventral nerve- 
cord, to form a half-moon-shaped band of cells. This band grows 
upwards round the gut, and forms the new oesophageal commissure and 
* Zeitschr. wiss. Zool., Ixiii. (1897) pp. 263-91 (3 pis.). 
t Jenaisch. Zeitsclir. Naturwiss., xxxi. (1897) pp. 105-52 (3 pis.). 
