S 68 
THE LOWEST ANIMALS. 
The spiral-mouthed animalcules (Spirostomum) are among the largest of the 
class, and visible to the naked eye, especially in sunlight, as slender golden threads 
about one-tenth of an inch in length. The body is cylindrical, and the surface 
covered with rows of cilia; the mouth- 
slit extends along; half the length of the 
under side, and is bordered on its left 
side by a fringe of long cilia. The 
animalcule is frequently twisted on its 
long axis, the mouth-cilia forming a 
spiral; multiplication takes place by 
transverse fission through the middle. 
The curious marine animalcule 
Acineta is probably related to the 
ciliated infusorians. The stalked club- 
shaped body is usually fixed on sea¬ 
weeds or Bryozoa. From the upper end 
a number of straight sucker-like ten¬ 
tacles proceed; a nucleus and also clear 
vesicles are present in the body- 
substance ; and the embryos are ciliated. 
The bud-bearing Hemiophrya is 
also a marine-animalcule; it possesses a 
few suckers and a larger number of 
longer prehensile tentacles; on its margin 
several buds are formed, each contain¬ 
ing a process of the nucleus, and the 
young forms when liberated are ciliated 
on their lower surface. The long tentacles capture and disable the prey, and 
bring it within reach of the suckers, which then surround and dissolve it, and 
finally appear to pump the newly-acquired nutriment into the general body- 
substance. 
R. KIRKPATRICK. 
i bud-bearing animalcule, Hemiophrya 
(highly magnified). 
spiral-mouthed animalcule, Spirostomum. a, Nat. size. 
