98 
MALCOLM LAUEIE. 
backwards into two large processes, and a pair of lateral 
cushions on the ventral wall of the siphon. The dorsal 
cushion is produced forwards into a papilla which is best seen 
in section (fig. 6, i.). Figs. 3 — G show sections through the 
siphon and Verrill’s organ. The valve (figs. 2 and 6, v.) is 
well developed, and quite distinct from Verriirs organ. 
An examination of the histological structure shows the 
organ to be glandular. It is composed (fig. 7) of columnar 
goblet cells almost entirely filled with a clear transparent 
substance which stains very darkly with hsematoxylin. The 
nuclei are at the bottom of the cells, and are surrounded by a 
small quantity of granular protoplasm. On the surface of the 
organ, more especially in the older specimens, there is a large 
quantity of mucus-like substance which has apparently been 
excreted from the cells. The organ of Verrill thus appears to 
be a mucus gland. It may, as Verrill suggests, function as a 
valve in those forms in which a true valve is wanting, but such 
a function would be secondary. 
It is well developed in Ommastrephes in specimens about 
8 mm. long. I can find no trace of it in the adults of either 
Loligo or Ommastrephes. 
As regards its use to the organism or its homologies outside 
the Cephalopoda, I can say nothing. I think that Verrill has 
no foundation for his suggestion 1 that the dorsal cushion is “ a 
true homologue of the foot of Gasteropods.” Its presence, so 
largely developed in the young, seems to indicate that it is an 
archaic structure in the group of Cephalopoda, but there are 
no grounds for identifying it with any particular structure 
existing in Gastropods. 
1 Loc. cit., footnote p. 432. 
