vine: carboniferous and permian polyzoa. 
81 
and Zooids, conveniently traced. And I infer from these studies, 
without going into special details, that similar actions took place in 
the formal development of the Zooecium, the polypide, and the colony 
of the species of Polyzoa found in our Paloeozoic Rocks. Mr. Hincks, 
speaking of the " specific functions" of the Endocyst, after quoting 
Joliet's views says that the French biologist " regards the Endocyst 
as speciall)' charged with the eidargement of the colony, and also as 
giving origin to a distinct tissue, which he names (provisionally) the 
Endomrc I do not say that I have read aright all the 
characters in these Pala30zoic forms, but I have endeavoured, both by 
descriptions and illustrations, to help others in the pleasant, but by 
no means, easy work, of tracing out and identifying fossil calcareous 
structures. 
Gonocijsts. So far as I am aware, this is the first time that the 
reproductive cells of Pal?eozoic Polyzoa have been figured, or I believe 
referred to specifically. In his Introduction to his British ^larine 
Polyzoa (pp. ii. and iii.), Mr. Hincks furnishes a very fair and some- 
what full chapter on " Terminology." In the introductory part of 
the present paper, I have adopted parts of this chapter for working- 
purposes. As regards the ovarian cells of the Cheilostomata, much 
detailed information may be found in two papers by Mr. Hincks,f 
and a rather full list given of species in which the ovicells can be 
conveniently studied. But in the above work the Ooecium (= ovicells 
auctt.), is defined as a ''special receptical, attached to the Zooecium, 
in which the ova complete their development into the larva," but the 
direct passage of the ova into the Ooecium has not been witnessed, 
nor have we, I believe, any observations showing by what means it is 
effected," (Op, cit., p. xciii.) As regards the history of the Gonocysts 
and Gonaccium we know but little, but their full definitions as given by 
Mr. Hincks, will be useful in the present division of my subject, so I 
shall not scruple in quoting them here. The Gonocyst is defined as 
an inflation of the Zoarium in which embryos are developed, while 
the Gonoecium is a modified Zooecium only, set aside for reproductive 
* Brit. Marine Polyzoa. Introduction p. xii. 
t Note on Ovicells, &c., Quart. Journ. Micro. Soc, 1861; and on " Germ 
Capsules,' Ibid, n.s., vol. xiii. 
