52 McMURRICH. [Vo. III. 
but that of the verrucz remained firmly attached, and could only 
be separated with difficulty, as in Awdactinia and Helactis. 
When separated, the cells composing it were seen to be exceed- 
ingly delicate and very uniform in thickness, being only slightly 
dilated towards the outer extremity. There were none of the 
glandular cells or cnidoblasts of the general ectoderm present. 
The darkly stained bodies seen in the sections were found to be 
small oval or pyriform structures, measuring 14.4 in their 
longer diameter, and with a maximum thickness of about 4.8 wu. 
It is possible that they may be glandular, but I was unable to 
discover that they possessed any connection with the exterior, 
though some of the more perfectly isolated ones seemed to be 
broken off at one end, and there may possibly have been a very 
fine process or duct extending to the surface. There appear to 
be no nerve cells present in the verrucal epithelium, unless these 
pyriform bodies be such, and no muscle cells. 
Von Heider observed (’77) in his investigation of Hedlzactis 
bellis (Sagartia troglodytes) that the ectoderm of the verrucze was 
less readily separable from the mesogloea than that of the general 
surface, and also perceived the difference in the shape of the cells 
which he describes as follows: “Eine solche (Saugwartze) mit 
Osmium oder Alkohol gehartet und untersucht (Fig. 38) erweist 
sich als aus zahlreichen parallelen Stabchen zusammengesetzt, 
die spindelformig und beiderseits ziemlich spitz endend, im 
Innern fein gekérnt erscheinen und so dicht aneinander gedrangt 
sind, dass die einzelnen Elemente nur am Rande des Schnittes, 
wo sie sich isoliren, deutlich zu sehen sind.” According to my 
observations, the spindle-shape was not so universal a character- 
istic, though some cells presented it. Von Heider did not 
observe any of the peculiar pyriform cells, and it is possible that 
they may not be present in the verruce of Hedzactzs, though it 
seems more probable that they were overlooked, as they might 
very readily be, in Bunodes teniatus, for instance. 
With regard to the mode of action of the verruce in pro- 
ducing the adherence of foreign bodies, Gosse (’60) was of the 
opinion that it was a process of suction, agreeing in this with 
Hollard (51) and Haime (’§4). I do not think this is the case, 
however. The absence of muscle cells in the verrucal epithe- 
lium, and the abrupt discontinuity of the muscle processes at the 
edge of the verruce as seen in sections of Awlactinza, are 
