MOSS’S POLYSTIGMATIC APPENDICULARIAN. 63 
and at the same time so shallow as the branchial canals of 
a Kowalevskia. Even Huxley entirely overlooked their 
homologues in his earlier observations upon the anatomy 
of Appendicularia; while Gegenbaur, who first noticed 
them, described them as leading from the pharynx into 
the general cavity of the body. 
The other and the chief discrepancy can also be 
accounted for, although the explanation to be offered 
involves the downfall of the character upon which the 
importance of Mossia has hitherto been chiefly based. 
The pharynx of Kowalevskia tenuis is provided with four 
longitudinal rows of ciliated digitiform processes, which 
project within its cavity. ‘Two of these rows are for the 
most part dorso-lateral in position, but anteriorly they 
bend round the wall of the pharynx and are united with 
one another in the mid-ventral region just behind the 
mouth; the two remaining rows are ventro-lateral, and 
they are similarly connected with one another in the mid- 
ventral line anteriorly, at a spot close behind the junction 
of the dorso-lateral rows. All four rows converge poster- 
iorly in the cesophageal region. The digitiform processes 
from these ciliated bands are longest in the middle and 
become gradually shorter towards each extremity. They 
project in such a way that the extremities of the dorsal 
processes almost meet the tips of the ventral ones of the 
same side; for the gradual approximation of the dorsal and 
ventral bands anteriorly and posteriorly compensates for 
the accompanying diminution in the length of the ciliated 
processes (fig. 8, DR, VR). 
The gill-like fold of the ventral wall of the pharynx ot 
Mossia, ‘“‘ wide in the centre and tapering to either end, 
extending from the posterior [1.e. ventral] lip of the bran- 
chial orifice to a point close to the insertion of the appendix 
[the tail] ,” is in my opinion nothing else than the expres- 
