1879.) 319 [Fewkes 
deviations in the normal course of the chymiferous tubes in the bell. 
Although their course is not so abnormal as that of the tubes 
in the smaller bell, it is still quite curious. Four chymiferous 
tubes arise from the single central tube which communicates 
with the stem cavity of the animal. Of these, three pass 
directly to the circular tube which they join, forming at the point 
of junction an enlargement. One of these continues along on the 
under side of the bell, following almost exactly the ridge, which forms, 
by being continued, the most prominent circumyelar projection of the 
bell. From its junction with the cireular vessel, where a conspicuous 
enlargement is formed, a secondary tube arises which extends along 
the bell almost parallel with the normal tubes, and when under the 
junction of the protecting plate and ridge of the bell enlarges and 
sends out three short digitate branches. I donot know what the 
homology of this secondary tube is. At times it arises not from the 
enlargement but from the vesselitself. The fourth of the four chym- 
ferous tubes, which arises from the common junction, passes a short 
distance down along the bell, and then divides, one part extending at 
right angles across the bell for about a quarter of the distance around 
the nectocalyx, and then turning again at right angles goes on paral- 
lel to its former course to join the circulartube. An indistinct draw- 
ing of a part of this tube can be seen in one of Kolliker’s plates, but 
is not mentioned in the text. The former of the two branches into 
which the tube is divided extends directly on to the vicinity of the 
digitate-like structure already mentioned, but is then not probably 
joined to it. Gegenbaur leaves nothing new to be said of this 
abnormal vessel. 
Such is the course of the tubes, not in a single specimen 
alone, but in hundreds of Abylae, as studied when alive or when 
acted upon by reagents. The tendency of the chymiferous tubes of 
the Acalephae to vary in their course is well known. ‘The constancy 
of form in this case seems to indicate that it is an anatomical peculi- 
arity of the bell. ‘The plate which covers the stem when it is drawn 
to the side of the bell, into the longitudinal canal, is not a ‘“ deck- 
stiick ’’ nor homologous to these structures. ‘The existence, however, 
of this plate or so-called canal, is no doubt the cause of the peculiar 
variation of the tubes from the usual arrangement. 
If we look for the homological solution of this plate we may con- 
clude that it is the recurved extended edges of the ridge rising on the 
side of the groove, which shelters the contracted stem. Similar 
