50 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [BulL, 



they have taken on a rosy color characteristic of approaching 

 maturity. Yet, in spite of the apparent ripeness of the sexual 

 glands, the sperm cells of many individuals lack the activity of 

 full development, and the eggs of the females when examined 

 under the microscope reveal their immaturity. 



In May the sexual glands have become so greatly distended 

 in well-fed individuals that the arms appear full and rounded. 

 The feather-like processes of the glands have now become so 

 delicate that a slight injury is sufficient to allow the sexual 

 products, eggs or sperm cells, according to the sex of the in- 

 dividual, to flow out freely into the water. From this time on 

 through the following month the eggs of a majority of speci- 

 mens can be easily fertilized artificially, and make extremely 

 interesting objects for the study of cleavage and early develop- 

 ment. Owing to the minuteness of the sexual products, how- 

 ever, a compound microscope is necessary for the study. 



To obtain the eggs for study plenty of clean sea water must be 

 at hand together with suitable receptacles of glass or porcelain. 

 Soup dishes or common tumblers are very convenient, but 

 must be kept covered. The starfishes must, of course, be kept 

 alive in sea water, and in order to insure ripe products of both 

 sexes a considerable number of specimens should be available. 



After placing clean sea water in one of the vessels a starfish 

 may be taken and, by means of strong scissors, opened by re- 

 moving the aboral surface of one or more of the arms. The 

 feather-like glands may be taken with a pair of forceps and 

 shaken gently in the vessel of water. A milky cloud issuing 

 from the cut end of the gland indicates that the specimen is a 

 male, the cloud itself being made up of thousands or millions of 

 sperm cells. If, on the other hand, instead of a milky cloud, 

 there issues a stream of tiny particles barely visible to the naked 

 eye, the animal opened is a female, and the little particles are 

 the eggs, or ova. Examination of a drop of the contents of 

 the vessel under a microscope will prove definitively which sex 

 has been obtained. One or more other starfishes must be opened 

 in a similar manner, the generative products of each being re- 

 ceived in a separate vessel, until the genital products of both 

 sexes have been obtained. 



After the eggs in on& of the vessels have settled to the 



