Tlic Dfyeloii 



PA-RT I, EXTERNAL. 



By SAMUEL F. CLARKE, Ph.D. 



Assistant in liie Biological laboratory and sometime Fellow of the Johns Ho|ikins University. 



In early March of 1878, I obtained in early stages of develop- 

 ment a number of eggs which I believed to be those of some 

 Urodele. They were found in considerable nutnbers in tiie pools 

 and small streams in and near the woods about Baltimore, dur- 

 ing the months of Marcli and April. They occurred in gelatinous 

 masses, Plate 4, Figure 30, which varied greatly in size, were usu- 

 ally more or less oval in shape, and attached to the stem of some 

 aquatic plant or to an overhanging blade of grass. 



This year I was so fortunate as to secure living specimens of 

 both sexes of Amb/i/stoma punctatnm before the females had de- 

 posited their eggs. They all did well iu confinement ; the males 

 furnisiied an abundance of spermatozoa at the critical moments, 

 the eggs passed through their various phases of development, and 

 a record of the external change is preserved by a series of camera- 

 lucida drawings. The animals derived from the eggs brought to 

 me in the spring of 1878, were studied with considerable care and 

 received considerable attention in respect to their food and sur- 

 rounding conditions. I was unable, however, to keep them after 

 they reached the abranchiate stage, and in consequence could not 

 determine what form I had been at work upon. I was much 

 pleased then to find ui)on carefully comparing the eggs laid by the 

 adults in my aquaria tiiis spring, their course of development and 

 their more advanced forms, that they agree in every particular 

 with the eggs and young forms which had occupied my attention 

 in the previous years. By getting the eggs in this way I was able 

 also to obtain the changes during segmentation, which I had not 

 gotten from my previous observations. 



The eggs, as I have said, occur in gelatinous masses, and these 

 vary in size from a small bunch of three or four eggs to a large 

 mass containing two hundred eggs and weighing sixteen ounces. 

 When the eggs are deposited in the water they are seen to be 

 covered with a very viscid, tenacious, translucent substance, of 



