162 
the zocecium, or cell. ‘To this view of Allman I must com- 
pletely assent, though I cannot go so far as to regard like- 
wise the ovarium and the testis as distinct zooids. 
Indeed I look upon every colony of “‘ Bryozoa entoprocta’”? 
as being a compound animal (“ Thierstock”’), composed of two 
different classes of zooids, the “‘ cystoid zooids”’ and the “ poly- 
poid zooids.” 'The cystoid zooids assume very different shapes, 
their various forms causing the great diversity of the external 
form of the Bryozoa. In this group are to be reckoned— 
1. The ccencecium of the Phylactolemata, showing not yet 
separated lodges (Lophopus), and the cells or zocecia of the 
Phylactolemata with distinct lodges, Chilostomata, Ctenos- 
tomata, and Cyclostomata. 
2. The avicularia of the Chilostomata. 
3. The ovicells or ocecia of the Chilostomata. 
4, The vibracularia of the Chilostomata. 
5. The stem-joints of the Vesiculariade. 
6. A part of the spines and root filaments of the Chilosto- 
mata and Ctenostomata (?). 
The primary zooid of every colony is a cystoid zooid pro- 
duced by a direct metamorphosis of a ciliated larva. 
The polypoid zooids are always produced by a process of 
budding from the inner side of the endocyst of a cystoid 
zooid ; but since only the two first-mentioned modifications 
of cystoid zooids are endowed with the faculty of producing 
polypoid buds, there are only two forms of polypoid zooids: 
1. The common polypide, generally considered as the in- 
testinal apparatus, and the tentacular crown of the polyzoon. 
2. The round bodies, bearing a brush of sensible sete, in 
the avicularia of some species.” 
The cystoid zooids are intrusted with the whole amount 
of reproductive functions, both sexual and asexual, the 
polypoid zooids providing for the nutritition, the respiration, 
and the sensitive functions, the functions of the polypides 
of the avicularia being limited to the latter function. 
Lastly, 1 must state that I cannot find any adequate rea- 
son to regard the so-called “nervous system of the colony ” 
as a true nervous organ. 
A more elaborate account of the facts leading me to this 
conviction I shall give in a subsequent paper. 
LEIpzie, 1st February, 1871. 
1 H. Nitsche, ‘ Beitrage zur Kenntniss d. Bryozoen. Zeitschrift fiir Wis- 
senschaftliche Zoologie,’ v. xx, p. 34. 
? Busk, “On Avicularia,” ‘Quarterly Journal of Microscopical Science,’ 
New Series, Vol. II, 1854, p. 26, Pl. IL. 
