1096 BULLETIN OF THE BUREAU OF FISHERIES. 



exterior as described above. The eggs when extruded have the adhesive disk 

 by which they become affixed to the nest. The formation of this disk and the 

 manner of fixation of the eggs are points on which the writer is unfortunately 

 able to give no information. The eggs are very large, measuring from 4 to 6 

 millimeters in diameter, the average being about 5 millimeters, as stated by 

 Miss Clapp (1891 and 1899) and by Ryder (1886 and 1887). 



The testis. — This organ, like the ovary, consists of paired elongated glands 

 lying in the posterior dorsal part of the body cavity. They are confluent 

 behind to form the sperm duct, which opens in the same place and manner as 

 the oviduct. .4 and B, figure i, plate cvii, show the dorsal and ventral surfaces 

 of the ripe spermaries of a full-grown toadfish and are natural size. The long 

 lobulated organs are the testes, the roundish dark structures are the paired 

 lobes of the bladder, while the short whitish bodies (placed posteriorly and 

 reaching right and left) are accessory glandular structures whose function is 

 not known. 



The spermatozoan is very large. The head is round in front, nearly as 

 broad as long, flat behind where it joins the middle piece, which is almost 

 as large as the head. The tail is not very long and the motion relatively slow. 

 The sperms resemble nothing in the world so much as tadpoles with very large 

 heads, and bodies but little smaller, behind which extend thin tails several times 

 longer than the head and body combined. 



FERTILIZATION AND EMBRYONIC DEVELOPMENT. 



Natural fertilization. — The manner in which fertilization is effected in nature 

 is not known, but it is interesting to note here the correlation between the size 

 of the micropyle and the sperm. The former is so large as to be visible to the 

 naked eye. 



Artificial fertilization. — Neither Miss Clapp (1891 and 1899a), in her experi- 

 mental work on the egg of the toadfish at Woods Hole, nor Miss Wallace (1898) 

 had any trouble in artificially fertilizing the eggs, since ripe males and females 

 were readily obtainable. At Beaufort scores of fish were dissected by the 

 writer in the course of this research during 1906 and 1907, but while ripe males 

 were abundant not a single ripe female was obtained. Fish were caught all 

 over the harbor, the extreme points of capture being 3 to 3X miles apart. On 

 July 18, 1906, in a tank of fishes from Cape Hatteras, I received 12 toadfish. 

 Two were given away, the Sex of one could not be determined macroscopically, 

 nine were males, and one was a female with immature ovaries. At Woods 

 Hole females are more abundant than males, I am informed by Mr. Vinal N. 

 Edwards. 



