ANATOMY AND PHYSIOLOGY. 
Moll. 33 
them ; the whole apparatus and the contained fluid suggest the lym- 
phatics of Yertebrates. The usual condition is one of turgescence, and 
the mass of blood is sufficient to account for all changes of volume of 
different organs, without the presence of pores for the entrance of water 
or exit of blood ; Houle (1). 
For experiments on the heart of Pulmonata ; see Richard. 
Innervation of the heart pi Helix ; Trambusti (p. 37, posted). 
The blood-vessels aud pulsations of the heart, at the rate of 50 to the 
minute, were visible through the skin of the living Helix thyroides ; 
Simpson (2). 
5 . Respiratory System. 
The gills of Fasciolaria develop as a series of folds on the dorsum of 
the veliger, uncovered by the mantle ; they afterwards become plate-like, 
and come to occupy the usual position, hanging on the inner surface of 
the mantle in a special cavity. The heart is at first in front of the gill, 
but as this is carried forward it is left behind. The adult gill has the 
same structure as in Fulgur , but its development is more primitive. 
The ctenobranch condition is regarded as being more primitive than the 
ctenidial ; Osborn (1). 
Davis, in opposition to Spongel, states that the rudimentary gill of 
Patella is covered by a continuation of the olfactory epithelium, and 
also that it is entirely made up of trabeculae of connective tissue. It 
may possibly have a function other than that of smell (? locality-sense). 
6 . Excretory and Secretory Systems. 
The elaborate paper of Frenzel (1) on the Molluscan mid-gut gland 
has been to some extent anticipated by preliminary communications [vide 
previous Records]. I. Histology (a) granular cells (liver-cells of Bar- 
furth) occur in all groups except Cephalopods ; they contain a spherical 
vesicular ball, enclosing pigment-granules, fat-globules, and masses of 
albumen. A hair-fringe is present, and is long in Cephalopoda and some 
Pelecypoda ; a ciliated fringe may have been derived from it. ( h ) The 
club-shaped cells occur in all types of Molluscs ; they contain a spherical 
ball, with more or less pigmented contents; fat and albumen are also 
commonly present. Their secretion is acted on by strong acids, thus 
differing from that of the granular cells, (c) Calcareous cells occur often 
but not always ; they contain calcium phosphate. II. Physiology: — The 
gland is said to have a digestive function in all cases, discharged both by 
the glandular and club-shaped cells. The calcareous cells ^are not secre- 
tory. No true constituents of bile could be demonstrated. So complex 
an organ probably discharges other functions hitherto unknown. 
The so-called “liver” of Cephalopoda , and also of some Prosobranchiata, 
contains only one kind of epithelial cell, comparable with the club- 
shaped ferment-cells of other Mollusca ; in these forms it must be 
regarded as digestive. In othor Prosobranchiata the cells are granular, 
and according to Barfurth the organ must here be regarded as a true 
liver. In the Opisthobranchiata there are two kinds of cells, and it may 
b3 a “ hepato-pancreas.” So many histological details are common to the 
