NEMATODE EGGS FEOM THE GILL REGION OF A 

 SHAEK, CARCHARHINUS MILBERTI 



By G. A. MacCallum 



Of Baltimore, Maryland 



On August 29, 1925, we examined at the United States Bureau of 

 Fisheries Commission at Woods Hole, a large shark, CarcharMmis 

 milberfi, which is sometimes called great blue shark, dusky shark, 

 etc. There were found on the gill arches or attachment of the 

 gills to the cavity of the throat some quite 

 large black patches on the mucous membrane. 

 On further careful examination these proved 

 to be deposits of eggs very like those found the 

 year previous on the under surface of the nose 

 of a Carcharhmus coinmersonii and reported 

 by MacCallum (192.5). The eggs appeared to 

 the naked eye similar to those preA'iously 

 reported by MacCallum, although their loca- 

 tion was different and they were laid in a dif- 

 ferent manner. Tliese were in very consider- 

 able patches, sometimes as much as two inches 

 long by half an inch wide or wider, and hence 

 quite different from those reported from a 

 shark last year by MacCallum, the latter eggs 

 being in almost mathematical!}^ correct 

 squares between the scales and if laid on the edges of the fins they 

 were found to be under the outer layer of the skin. On closer exam- 

 ination of those seen on C archarhinus m.ilherti they were found to be 

 covered with spines (fig. 1), not very closely placed, and visible only 

 under a high magnification. In other respects than this they were of 

 about the same size, color, and shape as those previously reported by 

 MacCallum. Those described here are 110/x. by GOjw. Apparentl}^ they 

 might belong to the same genus, although evidently of a different spe- 

 cies at least, and they may be tentatively referred to the genus CapiJ- 

 laria. As in the case of those eggs found on C. commersonii no adult 

 worms were found. By placing a few clean eggs between two cover 



No. 2655.— Proceedings U. S. National Museum, Vol. 70, Art. 6. 



4G84— 2G 1 



Fig. 1. — Eggs of Capil- 

 lauia spixosa? 



