62 APLYSIID^:. 



In Phyllaplysia the teeth are tricuspid, denticles broad and ob- 

 tuse (pi. 9, fig. 26, P. lafonti). 



In Notarchus the teeth are narrow with long cusps closely serrate 

 or barbed on both inner and outer edges. 



The buccal mass (pi. 62, fig. 4, bin) is large and muscular, two 

 much lengthened salivary glands (s. <;.) enter it, one on each side of 

 the long oesophagus. The stomach (s) consists of three portions : 

 an anterior thin-walled sack, a median hard and muscular belt 

 armed inside with pyramidal cartilaginous nodules for triturating 

 the food, and following this a thin-walled portion containing inter- 

 nally smaller nodules or spur-like appendages. This passes into the 

 intestine (f), which is coiled about the large liver or digestive gland 

 (d. <//.), the ducts of which, several in number, enter it near the 

 point marked x. Becoming free from the liver, the intestine crosses 

 the ovo-testis in a groove, and terminates externally at the base of 

 the excurrent siphon (see pi. 62, fig. 4, Aelesia pleii Rang; pi. 9, 

 fig. 15, Tethys punctata ; pi. 40, fig. 2, Notarchus punctatus Phil.). 



The genital system (pi. 62, figs. 1, 2, Aelesia pleii Rang) consists 

 of a hermaphrodite gland or ovo-testis (o. .) which communicates 

 spermatozoa and ova by a common duct, the small hermaphrodite 

 duct (h. d.), to the " annexed genital mass," G. In this mass the 

 hermaphrodite duct splits (fig. 3, div.) : by one branch (the Cu- 

 vierian duct, CuvJ), communicating with the spermatheca, sp., the 

 other branch, oviduct, involved in a complex series of convolutions 

 partly concealed in the annexed mass (fig. 3, diagrammatic, show- 

 ing convolutions of oviduct [ov.], Cuvierian duct [Cuv.~\ and sper- 

 matheca \_spj). The middle of the annexed genital mass is com- 

 posed of the albumen gland (alb.), visible only on the lower surface 

 of the mass. At the base of this mass is the spermatheca, sp. ; 

 downward is the greater hermaphrodite passage (ghd\ bearing be- 

 low the globular Swammerdam's vesicle ($. v.), which is functional 

 as a reservoir of spermatozoa ; and the female system ends below 

 this in the external opening (o). Thence the male system continues 

 as a groove or furrow in the integument passing forward to the 

 vicinity of the right anterior tentacle, where the penis is situated. 

 This organ ^seen retracted in pi. 62, fig. 2, and extended in pi. 37, 

 fig. 19) is grooved lengthwise, continuing the furrow just described, 

 for the passage of spermatozoa. It is retracted by a muscle at- 

 tached distally to the body wall (fig. 2, rm.). 



