270 EVENINGS AT THE MICROSCOPE 



part of the shell are eggs. Most of the females that we 

 meet with carry one or more, sometimes to the number 

 of six or seven. The specimen we are examining had 

 two at first, one on each side the foot-orifice; but just 

 now a third was excluded an operation which occupied 

 but an instant and this took its place beside the former 

 two, so that we now see three. These eggs are generally 

 carried by the parent until the young are hatched. The 

 oldest of these three is nearly ready for hatching, and if 

 you watch a while you will see the birth of the young. 

 At first exclusion, the egg which was seen some time be- 

 fore in the ovary, as a semi-opaque mass, of well-defined 

 but irregular shape, immediately assumes a form perfectly 

 elliptical, and its coat hardens into a brittle shell. This 

 is so transparent that the whole process of maturation can 

 be watched within the shell. The yelk is at first a turbid 

 mass, in which are many minute oil-globules. Soon it 

 divides into two masses, then into four, then into eight, 

 sixteen, and so on, by the successive cleavage of each 

 division, as fast as it is made, till these divisions are very 

 numerous. Then we begin to see spontaneous movements; 

 the outline of the young separates in parts from the wall 

 of its prison, folds are seen here and there, and fitful con- 

 tractions and turnings take place. Soon an undefined 

 spot of red appears, which gradually acquires depth of 

 tint and a definite form, and we recognize the eye. Slight 

 waves are seen crossing one end of the egg; these become 

 more and more vigorous and rapid, and at length we see 

 that here is the situation of the frontal cilia. The mastax 

 appears, and the jaws, and soon the latter begin to work; 

 though it must be only by way of practice, for it is hard 

 to imagine what they can yet find to masticate. 



