52 LIVERPOOL BIOLOGICAL SOCIETY. 
tissue closely surrounding the whole intestinal canal. 
‘Carefully examined,” he says, “this tissue is found 
composed of closely aggregated glandular sacs, which 
empty their contents into the intestine either directly 
or by many common secretory ducts. The contained — 
liquid is, with most species, a transparent fluid in — 
which are suspended brown granules, and it resembles — 
the bile of the higher animals.”’ 
Claparéde* describes yellow cells as arranged round the — 
vessels opening into the dorsal vessel, but throws no light — 
on their function beyond saying that, in his opinion, they 
do not give rise to the corpuscles of the ccelomic fluid as 
stated by some observers. 
Ray Lankestert does not consider the corresponding © 
cells in the leech as hepatic at all, but believes them to — 
be ‘‘ vasifactive.”” Beddardt describes the yellow cells of © 
Pleurocheta moseleyt as simply cells lining the cclomic 
cavity, and not opening into the alimentary canal at all. 
The yellow cells are also briefly referred to by Perrier.§ 
In the text books these statements reappear, with or 
without criticism. Huxley,|| for example, merely remarks 
that “‘ the exterior of the intestine and the cavity of the 
typhlosole present a coating of yellowish-brown cells.” 
Marshall and Hurst] describe the ‘‘hepatic cells” as 
being ‘‘a layer of yellow cells surrounding the intestine, 
and in close relation with blood vessels. Their function 
* Recherches anatomiques sur les Oligochetes, Mem. de la Soc. de Phys. de 
Geneve. Vol. xvi., p. 217. 
+ ‘£On the Vasifactive and Connective Tissues of the Medicinal Leech.” 
Q. J. M. S., vol. xx., 1880. 
+ The Anatomy and Histology of Plewrocheeta moseleyi. Trans. Roy. Soc., 
Ed., vol. xxx., pt. ii. 2 
§ F. Perrier, Organisation des Lombriciens Terrestres, Arch. d. Zool. Exper., 
lii., 1874. 
Anatomy of Invertebrated Animals. 1877, p. 223. 
{] Practical Zoology. 1887, p. 61. 
