MALE. 201 



sexes cohere, but are essentially distinct : " this singular 

 species, however," according to Professor Owen,* " offers 

 the transitional grade to that still more extraordinary 

 Entozoon, the Syngamus trachealis, in which the male is 

 organically blended by its caudal extremity with the 

 female, immediately anterior to the slit-shaped aperture 

 of the vulva. By this union a kind of hermaphroditism 

 is produced ; but the male apparatus is furnished with its 

 own peculiar nutrient system ; and an individual animal 

 is constituted distinct in every respect, save in its terminal 

 confluence with the body of the female. This condition 

 of animal life, which was conceived by Hunter as within 

 the circle of physiological possibilities, has hitherto been 

 exemplified only in the single species of Entozoon, the 

 discovery of the true nature of which, is due to the sagacity 

 and patient research of Dr. C. Th. Von Siebold." In 

 Ibla, the males and females are not organically united, 

 but only permanently and immovably attached to each 

 other. We have in this genus the additional singularity 

 of occasionally two males parasitic on one female. 



I have used the term parasitic, which perhaps ought 

 strictly to be confined to cases where one creature derives 

 its nutriment from another, inasmuch as the male is in- 

 variably and permanently attached to and imbedded in 

 the female, — from its being protected by her capitulum, 

 so that its own capitulum is not developed — and from 

 its feeding on minute animals infesting her sack. The 

 male Ibla must seize its prey, guided probably by its 

 well- developed olfactory organs, through the movement 

 of its long, flexible body, furnished with muscles, and 

 with the mouth seated on the summit. We have already 

 seen one instance of a Cirripede, the Anelasma, obtaining 

 its food without the aid of cirri, by means of its pro- 

 bosciforaied, flexible mouth. The eye can serve only to 

 announce to the male when the female opens her valves, 

 allowing occasionally some minute prey to enter. In 



* Cyclopaedia of Anatomy and Physiology, p. 142. 



