1879.] 323 [Fewkes. 
I give a figure of an Epibulia in my collection which illustrates this 
point. An objection to a comparison of this kind would be that we 
have in one a superior part of the first nectocalyx, and in the other, 
the inferior of the second. ‘The two nectocalyces of Diphyes, Abyla, 
Epibulia and Praya, are probably homologous. The smaller, or an- 
terior as they swim, may be called the superior, and the larger the in- 
ferior nectocalyx. It seems to me that the terms superior and inferior 
as applied to the nectocalyces and to the sides of the same would be 
preferable to proximal and distal, for then, since we have a right and 
left side to the bell, there would be more uniformity in the names of 
different sections. A somatocyst is, with one exception, confined to 
the superior bell. It is, however, almost impossible to homologize the 
different spheromeres of the inferior nectocalyx of Abyla, Diphyes 
and Epibula. Along the medial line of the inferior side of Epibula 
passes a chymiferous tube. Where is this tube in Abyla and 
Diphyes? I have found nothing in either of these genera to repre- 
sent a tube along the medial line, and lying in a plane, in refer- 
ence to which such a bilateral symmetry exists as we find in 
Epibulia. 
Closely connected with the discussion of the homology of the 
chymiferous vessels in Abyla, the importance of which in an appre- 
ciation of bilateral symmetry among Siphonophores cannot be over- 
looked, comes the question of the relationship of certain appendages 
to the lateral tubes in Apolemia. These vessels I have figured and 
lettered j in figs. 2 and5. Leuckart (Zeitsch. wiss. Zool., p. 10), finds 
in them the representatives of the Mantelgefasse of Agalma, Praya, 
and Gleba. He says: “ Bei Apolemia werden diese Kaniale (Mantel- 
gefasse) von mehreren kurzen fast zottenformigen Gefiassausstiilpun- 
gen vertreten, die unter rechten Winkel aus dem obern Bogen der 
Seitengefasse hervorkommen und in die Substanz der Schwimm- 
glocken hineinragen.”’ 
I figure, I think for the first time, a single such vessel, fig. 67, 
appended to the lateral tubes of Epibulia. 
In my figure of the nectocalyx of the Apolemia I have represented 
in addition to these structures a true Mantelgefass not unlike the 
same structure in Gleba. It seems tome more natural to compare 
the tubular appendages in figs. 2, 5 and 6 with the connecting 
branch & fig. 5, than with the so-called mantle vessel which is the 
