TRANSACTIONS OF MICROSCOPICAL SOCIETY. 
DESCRIPTION OE PLATE IV, 
Illustrating Mr. Rainey^s paper on Artificial Calculi. 
Fig. 
1. —-a. Globular carbonate of lime in all states of coalescence. 
Crystals of triple phosphate becoming globular. 
c. Crystals of carbonate of lime becoming globular. 
2. — Globular carbonate of lime with triple phosphate (not laminated). 
3. — Globular crystals of carbonate of lime with triple phosphate (lami- 
nated). 
4s. — Globular carbonate deposited at the bottom of the bottle after stand- 
ing twelve months. 
5. — Globular carbonate deposited in lines and coalescing as in the prawn's 
shell. 
6. — Porous globules undergoing disintegration in gum -water, after two 
months. 
7. — Prawn shell simply dried and placed in Canada balsam. 
8. — Calcifying shell of crab (very early stage). 
9. — Calcifying shell of oyster (very early stage). 
Illustrating Dr. Cobbold^s paper on Actinotrocha.^ 
10. — Lateral view of the larva with the epistome partly raised, exposing the 
mouth. 
11. — Posterior aspect showing more particularly the terminations of the 
incomplete circle of branchial tentacula. 
12. — Position frequently assumed by the sudden approximation backwards 
of the epistome and caudal extremity. 
* Figures magnified 40 diameters linear. 
