Procoplialic Lobes of Epeiru Cinerea. 419 



Patten, in 1898, in his paper on color vision, has given a more 

 detailed account of the remarkable stnicture of the retinal elements 

 in the eyes of Lycosa, calling- attention more especially to the rela- 

 tion the form of the retinal cells bear to their position in the head 

 and to the direction of the rays of light falling npon them. 



II. Materials and Methods. 



In the following observations use was made of the eggs of Epeira 

 clncrea; all of the materials being collected in, or about, Hanover, 

 New Hampshire. This spider is one of the largest to be found in 

 northern ISTew England, which, together with its habit of infesting 

 houses and barns where, as a general thing, its nests are made in 

 easily accessible places, and the fact that the eggs are relatively large 

 and are, therefore, easily handled, renders this material well adapted 

 for emhryological work. 



The eggs are bound in a firm yellow mass in the cocoon, being 

 held together by a kind of cementing substance which is probably 

 secreted during their passage through the oviducts from the walls 

 of the duct. They can be easily removed from the cocoon by cutting 

 its walls away with scissors, and carefully manipulating the cut edges 

 with forceps. Considerable care has to be exercised in isolating the 

 eggs, as the membranes are easily ruptured. By cautiously forcing 

 them out of the mass with needles, the majority of them may be 

 removed without injury. This process is aided by their natural 

 elasticity which is very great. 



Three methods were employed in killing and fixing the eggs after 

 they had been separated. The first was to plunge the eggs into 

 water heated to Y0°-80° C, and afterwards transferring them to 95 

 per cent alcohol in which they were hardened. Then they were placed 

 in 70 per cent alcohol in which they wore preserved. This is the 

 method employed by Locy and Kishinouye. Unfortunately, how- 

 ever, it did not give good results except in the older stages ; the 

 yolk, in the earlier stages, showing a tendency to crumble and fall 

 to pieces. 



The second method was to kill the eggs in hot Perenyi's fluid, 

 the eggs being left in the fluid from twenty to thirty minutes, or long 



