NO. 1302. AMERTCAX PARASTTIC ARGULID.I^WILSON. 657 



It would be expected that the method would differ in different spe- 

 cies, and it actually docs vary in several particulars when witnessed in 

 A. (■(/fo-^fo/i// iiud A. Ill, (Jill ops. 



In the former species the female does not twist from side to side nor 

 do the egg-s alternate in two adjacent rows, as described by Jurine. 



In the deposition of hundreds of eggs no female was seen to de- 

 posit two rows at the same time, but only a single short row. 



These eggs of A. catostomi are ellipsoidal, quite large (O.-tS mm. 

 by 0.3 mm.) and are yellowish white when first laid. 



But they soon become dirty, turning first a darker yellow and finally 

 a rusty-brown color. The thick jelly with which tney are covered 

 when the}' come out of the oviduct quickly hardens in the water and 

 forms a dense covering, vei-y diflicult to break open without injury to 

 the ^.^'g inside. But the chief characteristic is the form which this 

 jelly envelope assumes. At hrst it is s])rt^ad in an even layer over the 

 entire ^^^^ but the surface ([uickly breaks u]) into longitudinal grooves 

 with sharp ridges between. The groox cs may or may not twist a little 

 spirally around the long axis of the (\ug. but the intervening ridges 

 always crack transversely and separate into short masses which usually 

 assume quite a perfect ellipsoidal form, the same as that of the ^gg 

 itself. 



These ellipses may lie arranged end to end in a row, similar to the 

 anangement of the eggs, or th(\v may be placed side by side, or may 

 even stand out at right angles to th(> surface of the ^,<gg like rounded 

 warts or papilla' (fig. 1). 



On further hardening, tlu^ sam<^ grooving and breaking up into 

 papilla' may apjx'ar on the sui'facc of cadi of the original (dlipsoids, 

 so that such eggs come to lia\(' a set of doubly crenated ribs, a mark 

 which will distinguish them wlierexcr found. 



The eggs of .1. ((iDrrlcdnus reseinl)le those of ,(if(,stoin'i in that the 

 jelly envelope breaks up similarly into longitudinal rows of papillae, 

 but there is nexcr any double crenation. In addition to the rows of 

 papilhv they are always from one to several much larger, irregular 

 mass(\s of jelly aitavhiHl to each egg ei:\'elope. 



The other species, A. unynlnp.s, is the tii'st of the salt-water Argulids 

 whose method of egg deposition has e\er ]>een watched, and the proc- 

 ess is therefore worthy of a somewhat more detailed description. 

 Through the courtesy of Vinal X. Kdwaixls a))Out a dozen females 

 with ripe eggs were o])tained from ^Voods Hole, on October 30, 1901. 



These were sent 1>y mail in a small bottle of salt water and were all 

 alive when received; some of them had already begun to deposit their 

 Qgg^ on the sides of the bottle on the way. 



The remainder of the eggs were secured on the sides of a small glass 

 aquarium to which the Arguli were all transposed. 



In this case also the female hunted for a suitable spot when about to 

 Proc. N. M. vol. XXV— 02 42 



