540 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. 



directed toward the upper albumiaous coating, which in many cases 

 shows very slight subhexagonal or circular depressions or elevations 

 corresponding to the position of the extremity of the egg beneath, just 

 as in Gorydalus the i^osterior ends of the eggs show "like faint dots 

 through the white covering". The outer albuminous coating appears in. 

 the fossil to be made up of as many parts as there are eggs, the inter- 

 ovular fibrous material extending to the surface of the ootheca, forming 

 walls to deep cells which contain eggs, and which are corked up, as it 

 were, by plugs of albuminous material. These plugs seem to be very 

 similar to the cell- walls, having been composed apparently of viscous 

 threads, also running in the same direction as the longitudinal axis of the 

 egg} but in some cases the cell- walls beyond the eggs have become 

 blackened, while the plugs retain their normal color, and separate readily 

 from them. 



When the egg-mass was undisturbed, the outermost eggs lay horizon- 

 tally, and those next the median furrow vertically ; the division walls of 

 the cells were therefore thinnest below, and it appears probable that the 

 young made their escape at the bottom of the median furrow, where the 

 outer coating is also thinnest. Where double layers occur, the eggs of 

 the upper seem to be in a direct line with those of the lower layer, egg 

 for egg, as if a ceil of double length were stocked with two eggs, sep- 

 arated by an albuminous partition ; and in this case the albuminous 

 floor and covering are thinner than usual, so that the egg-mass is not 

 greatly enlarged nor distorted. When two layers were thus formed, 

 the young larvae of the ui^per layer must have escaped through the 

 emptied cells of the lower. 



It only remains to add that with a single exception these masses differ 

 comparatively little in size, most of them being nearly or quite five cen- 

 timeters long, although some scarcely exceed four centimeters. The 

 single exception is of a mass only a little more than fifteen millime- 

 ters long, six millimeters broad, and three millimeters high. It shows 

 no furrow, but may represent only one lateral half of an egg-mass, as 

 the walls of one side are steeper than those of the other, and look like 

 the sides of a median furrow. This mass is so small that only by pre- 

 suming one-half to be gone, and the albuminous covering to be thinner 

 than usual, can it be regarded as belonging to the same species with the 

 others, although evidently of a similar nature. In case it belongs to the 

 same species, it may be looked upon as probable that a female usually 

 deposited all her eggs in a single bunch, but that some accident pre- 

 venting it, the remnant were in this case subsequently laid in a mass of 

 much smaller dimensions, one-half of which is preserved. This is the 

 view I am disposed to adopt. 



HOLCORPA {ul/.ai-q, upr.rj). 



This name is proposed for a genus of Panorpidce, unquestionably allied 

 to Panorpa, but differing remarkably from it in the total absence of cross- 



