ISJJ Dr Grant oti the existence and uses q/' Cilice 



Purpura lapillus, with the view of determining the influence 

 exerted by the enormous pulsations of the heart of the testa- 

 ceous gasteropodous niollusca^ in causing the oblique spire of 

 univalve shells to lie always on the side opposite to that or- 

 gan, I was early struck with the rapid and incessant motion 

 of the amniotic fluid towards the fore part of the body of 

 these animals during every stage of their developement within 

 the ovum, and it was easy to observe by the aid of the micro- 

 scope that these currents were produced by cilice placed around 

 the margins of two funnel-shaped projections on the fore part 

 of the young animal. On examining the cells newly deposited 

 by the female Buccinum undatwn^ whether in basons of sea 

 water, or on the sea shore, we find in each cell about a thou- 

 sand very small yellow opaque spheres, suspended in a trans- 

 parent gelatinous fluid, which has a saline taste, and leaves 

 dendritic crystals on evaporation. These yellow bodies do 

 not effervesce in nitric acid, nor can we perceive any lime se- 

 creted in the shell of the young animal before it comes in con- 

 tact with the sea water by the opening of the cell at maturity. 

 The yellow spheres are observed to assume an arrangement in 

 curved and convoluted rows, and at length they are found 

 grouped together into about twenty small separate masses, 

 where they are united by a gelatinous basis. Soon after the 

 formation of these twenty round groups, we observe the gela- 

 tinous connecting matter form a transparent covering on each 

 group, which is the rudiment of the future shell, and on one 

 side the gelatinous matter is lengthened outwards, so as to 

 form the margins of an internal cavity whose entrance is sur- 

 rounded with vibrating cilice^BXid in the interior of whichwe per- 

 ceive a constant revolution of the particles of some fluid. The 

 vibration of the cilicB^ and the revolving current in the internal 

 cavity, are perceived long before the pulsations of the heart, or 

 any appearance of that organ are discernible, and are the first 

 indications of life in the embryo. The yellow opaque bodies oc- 

 cupy the shut end of the spire like the testicle and ovarium of 

 the adult. The heart is formed on the left side of the trans- 

 parent anterior part, and its motions are so great, that at each 

 diastole the whole projecting anterior half of the animal is 

 forced considerably to the right side, causing that part of the 



