MOSS’S POLYSTIGMATIC APPENDICULARIAN. 65 
The above considerations have led me to conclude that 
the Appendicularian described by Surgeon Moss has no 
special resemblance to Doliolum, but has a structure which 
is all but identical with that of Kowalevskia tenwis. The 
similarity between these two creatures in some of their 
most leading characteristics (shape of the tail and mouth, 
position of the anus) 1s very marked, and they apparently 
agree with regard to several other points (absence of heart 
and endostyle, shortness and extent of the branchial 
canals). This resemblance between the two forms is so 
complete that, if our knowledge were confined to these 
facts, the generic identity of Mossia and K. tenwis would 
be at once recognised. The only statement opposed to 
this conclusion is in itself improbable, and is based upon 
appearances which are capable of another mterpretation. 
The explanation which has been suggested makes the 
connection of Mossia with other Appendicularians quite 
clear, and, if it be accepted, the structure and relationship 
of this form will no longer remain a mystery. 
Beyond this point, however, we cannot justly go. These 
two animals may be considered as members of the same 
genus, but it is advisable, for the present at any rate, to 
regard them as specifically distinct, on the ground of the 
following minor differences.—Firstly, Fol states the length 
of the tail and body in Kowalevskia tenuis to be respec- 
tively 8 and 1.1 mm.,—that is, in a proportion of 7.27:1; 
while a careful calculation of the length of the same parts 
in Moss’s species, as determined from his figure and scale, 
gives a length of from 3.556 to 3.685 mm. for the tail and 
of 0.635 mm. for the body,—a ratio of only from 5.6 to 
5.8:1, and this ratio would possibly have become still 
smaller when the specimen drawn by Moss had become 
fully mature, and its body distended with genital products. 
Secondly, the caudal muscle-bands of K. tenwis are narrower 
5 
