450 T. J. EVANS 



takes up no dyes, acid or basic. The fact that no other AeoHdio- 

 morph possesses such a glandular appendage of the penis adds 

 to the interest of this coincident acquisition of primitive 

 position and structure. 



The female duct is in very young specimens a straight 

 broad tube leading from the bifurcation of the sperm-oviduct 

 to the exterior. During growth this is differentiated into 

 a dorsal, much-coiled oviducal passage and a ventral straight 

 pathway for the introduced spermatozoa. The dorsal coils 

 (1.2.3.4 and sh.g.) are folds of the greatly enlarged female duct, 

 and in the figure are shown to form a continuous tube. In 



Text-fig. 3. 



sp.p. 



v.d. 



Section through the female complex at lr iii Text- fig. 2. e.p. 1.2.3.4, 

 folds of the oviduct through which the eggs pass ; 5, path of sperm 

 migration downwards; v.w., thin ventral wall of the oviduct; 

 v.d., vas deferens. 



surface view the coils project as two bulges, one on the left in 

 front and the other behind and on the right. The former has 

 been by common consent called mucus or nidamental gland, 

 and appears in pickled specimens of the Opisthobranchs as 

 a brittle white mass, swelling in water, while the latter is named 

 albumen gland. Many authors have stated or conveyed the 

 impression that these lobes are dependent glands opening by 

 ducts into the oviduct and pouring their secretion on the eggs 

 as they pass. The long continuous tube here described, how- 

 ever, comprises both lobes, and is actually the functional oviduct 

 through which the eggs pass, and in which they receive the 

 successive layers of nidamentum. The first or posterior lobe 

 (sh.g.) is composed of a coiled portion of the tube which is 



