44 TESTACEA. 



a central white embryonic nucleus. The mass is above a line and a half 

 in diameter, very transparent ; the integuments of its contents are hardly 

 discernible from extreme tenuity. Eacli of the young has a very slow 

 revolution within its own peculiar capsule, as advancing towards maturity. 

 The black eyes are then visible, and the sole still clumsily projects from 

 the body. 



This animal begins to breed at an early age. In confinement the 

 spawn is usually deposited on the side of the vessel, close to the surface 

 of the water. 



Plate IX. 



Fig. 5. Phi/sa fontinalis, viewed from above. 



6. Under surface. 



7. Shell. 



8. Spawn. 



9. The same, enlarged. 



10. Mass of Spawn, containing three capsules, w^ith theirembryos enlarged. 



11. Embryos in their respective integuments. 



■ LiMNJius ?— Plate IX., Figs. 12, 13. 



Length of the shell five or six sixteenths of an inch ; volutes three, 

 the first two very small ; animal a Umax, the length of the shell ; form 

 of the head obtuse ; tentacula short ; a black speck or eye near the sum- 

 mit ; sole oval ; colour grej'ish purple. Colour of the shell brownish 

 grey ; rare. Feeds on the decaying leaves of the iris. I have found this 

 both on the margin of ponds and in the water. 



A specimen which had retreated dry within the shell for six months 

 developed itself when moistened with water; rare.— Plate IX. Figs. 12, 13. 



MISCELLANEOUS. 



Fusus CORNEUS. — Plate X. Figs. 1, 2. 



This is among the larger and more symmetrical of the Scotish shells 

 inhabited by a Umax. 



