PI. VIII. 



mt. — mantle. 



ml. — mantle lobes. 



rp. — penis retractor. 



p. — penis. 



2?^.-*-vas deferens. 



o. — ovum. 



ut. — uterus. 



rs. — receptaculum seminis. 



alg. — albuminous gland. 



hd. — hermaphrodite duct. 



Jig. — hermaphrodite gland. 



a. — anus. 



Jco. — kidney opening. 



/. — lungs. 



Jed. — kidney duct. 



h. — kidney 



Figs. 1 and 2 exhibit the anatomy of Strept. oltusus, (see p 

 161) ; the letters have the following significations: 

 /.—foot. h.— heart. 



li. — liver. 



t. — intestines. 



c is the cavity where the ge- 

 nerative organs were ori- 

 ginally situated. 



st. — stomach. 



ng. — nervous ring. 



t. — eye-pedicles. 



roe. — retractor of the mouth. 



ac — tube including the radula. 



oe. (in figure 2) — ditto. 



rm. — chief retractor of the ra- 

 dula. 



ad. — anal albuminous gland. 



sg. — salivary glands. 



Fig. 3 shews the general arrangement of the teeth on the radula of 



St. oltusus. 

 Fig. 6. Side view of St. Pfeiferianus from the Nicobars ; nat. size. 



Fig. 7. Side view of Ennea[_Hutto?iella~]bicolor, from Calcutta; 

 twice the natural size. 



In figs. 4, 5 and 8 the numbers indicate the distance of the teeth 

 from the centre line. 



