190 Mr. A. Hancock on the Anatomy of the 
similar in all the Bryozoa, only those at the inferior extremity 
of the stomach im the marine species appear deficient in the 
freshwater forms. They all have, however, one or more appen- 
dages to this part, but these we shall afterwards see are most 
probably connected with the reproductive system. The parietal 
and sphincter muscles are common to both Paludicella and the 
marine forms. On the whole, then, im the muscular system as 
well as in the digestive apparatus, Paludicella shows a close re- 
lationship to Bowerbankia and its congeners ; and is, in fact, 
an intermediate link between them and the other freshwater 
Bryozoa. Even the minute structure of the muscles themselves 
would seem to confirm this. In all they are composed of trans- 
parent, linear fibres separated from each other and apparently 
homogeneous. When broken they become irregularly nodulous ; 
but I have not succeeded in detecting transverse strize observed 
by Professor Allman, probably from having used insufficient mag- 
nifying powers. The smal] knot-lhke swelling so remarkable in 
the centre of the fibre of the marine species is not to be found in 
either Plumatella or Fredericella ; im Paludicella, however, I have 
observed it in the parietal, but im no other muscles. 
Reproductive System.—In the freshwater as in the marie 
Bryozoa there are two methods of reproduction,—one by buds, 
the other by eggs. The buds always germinate from the same 
part of the cell, “hence the definite form of the polypidom. In 
Fredericella the germ is found in connexion with the imner sur- 
face of the tunic not far below the orifice of the cell on its lower 
side. As the bud enlarges the wall bulges, showing externally 
the appearance of a new shoot. At first the bud, Pl. II. fig. 3a, 
is small and oval, and is attached for nearly its whole length ; it, 
fig. 2.0, soon becomes irregular in form, with the upper portion 
broad and somewhat bifid, the lower extremity prolonged: the 
upper portion then gradually exhibits a circle of short rudi- 
mentary tentacles, fig. 4/7; and the lower end is seen to be di- 
vided jongitudinally_ into ‘cesophagus and intestine, fig. 5 3, d, 
continuous at their lower extremities, which still elongating form 
the stomach, figs. 4m & 5c. To this is seen an appended fila- 
ment binding it below to the wall of the cell. Imbedded in this 
filament there is a large, distinct globule with nucleus and nu- 
cleolus: this we shall afterwards learn is the incipient ovum, 
figs. 4 0 & 5 e, lying in the ovary. The polype-retractors, 
figs. 2 ¢ & 4n, now make their appearance, passing from the 
tentacular base to the side of the cell formed apparently out of 
the lower portion of the original attachment of the bud; the up- 
per portion of this attachment dilating becomes the tentacular 
sheath, fig. 2 p, into which the tentacles are gradually msinuated 
as they are developed: The polype being now, as it were, 
