DESCRIPTIONS OF ARGULID.E— WILSON. 



(337 



Eggs and deveIop7ne}it.—Gur\ey, in the manuscript already referred 

 to, has given an outline of devolopniont, with a description of the larva. 

 But, again, the present author had obtained ripe females from Professor 

 Reighard at Ann Arbor, Michigan, and had successfully reared the 

 larva' before Ourlev's manuscript was 

 placed in his hands. It is a pleasure 

 to find that these two accounts agree in 

 every detail. 



The eggs are laid in single rows (tig. 

 14). exacth' as those of A. inegalops^ 

 and not at all resembling either A. 

 fol Ulceus or A. catostonii. But the 

 eggs themselves are more like those of 

 A. eatostom! than of any other species 

 whose eggs are known. 



The}^ are arranged end to end, the 

 heads all pointing in one direction, but 

 with every third or fourth one re- 

 versed. The jelly in which they are 

 enveloped, on hardening in the water, 

 assumes an appearance verv similar to 

 that on the ^gg^ of ^4. catostoin'i — that is, it is raised into ridges run- 

 ning lengthwise of the ^gg^ each ridge composed of a row of club- 

 shaped papilla? standing out at right angles to the surface of the ^gg 

 (tig. 15). There are about six of these rows on the free surface of the 

 eggs, including those along the sides where the eggs are attached to 



Fig. 1h.— Posterior legs and abdomen 

 iif argulus americanus. 



'■n 



Fig. 14.— Mk'ro-photograph of egg string of argulus americanus, showing the .IELI.Y PRO- 

 tiberances and the larv.e partially developed. 



the surface on whic4i they are laid. The rows coalesce at tlie ends and 

 are most widely separated at the center. 



In addition to these crenated ridges there are also a few large scat- 

 tered masses of jelly, some of whicli are nearly two-tiiirds as large as 



