480 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [26] 



developmeutal history agreeing fully with this interpretation, in that it 

 is unusually rapid. For example, the eggs of Julis hatch in fifty-two 

 hours, Scorpccna in fifty-eight hours, Fierasfer in fifty eight to sixty 

 hours, without the slightest trace of pigment having yet appeared on 

 the eyes, so that when the eggs are ready to hatch, they are still as 

 transparent as at the time they were laid. 



" I observed the following in watching the first phenomena of impreg- 

 nation. In bony fishes, the first segmentation nucleus is formed as in 

 numerous other animals, by the conjugation of two nuclei. One of these 

 two nuclei is the egg nucleus (female in'onimlens, pronucleus femelle), the 

 other the spermatic nucleus (male pronucleus, pronucleus male). The 

 conjugation of these two nuclei is best seen in the beautiful, pellucid 

 ova of Scorpwna and Julis, as well as in the less transparent eggs of 

 Crenilabrus ; in the cases of other species of osseous fishes investigated 

 {Reliasis, Gobius, Clupea, etc.), the ova are not clear enough to enable 

 one to reach a conclusion in regard to this important point. 



"As soon as a spermatozoon has penetrated so far into the micropylar 

 canal that it reaches the germ disk, or perhaps the direction spindle it- 

 self, the first phenomena involving the spindle and germ appear in their 

 order. Around the lower pole of the spindle there is formed a small, 

 clear protoplasmic mass; whether a similar feature is developed at the 

 upper pole of the spindle it is difiQcultrto say, since this lies so close 

 against the inner opening of the micropyle that it is not possible to be 

 certain as to just what occurs here. The protoplasmic granules which 

 are scattered irregularly through the egg gradually aggregate more and 

 more around both poles of the spindle in distinct radial lines, especially 

 around the SDiall, clear protoplasmic area around the lower pole ; shortly 

 afterwards the development of the well known caryolytic figures is 

 accomplished forming the amphiaMer de r^but of Fol. Scarcely have 

 the radial figures [asters] become distinct, or at about the same time, it 

 may be observed that the germ begins to contract [aggregate] at the 

 micropylar pole. The first changes in the spindle now also begin, and 

 it becomes at first somewhat shorter and thicker. The same remark 

 applies also to the nuclear plate, when it again assumes its earlier form, 

 and thereupon again elongates, becoming gradually thinner and thin- 

 ner, before finally disappearing altogether. As soon as the spindle be- 

 gins to elongate, the division of the nuclear plate occurs. The nucleus 

 formed from the central half of the spindle is the egg-nucleus [female 

 pronucleus] ; that formed from the peripheral half of the spindle is the 

 polar body, which in IScorpccna, Julis, and Crenilabrus escapes from the 

 egg through the micropylar canal. Inasmuch as the division of the 

 spindle begins as soon as the spermatozoon has penetrated deep enough 

 into the micropylar canal to come into contact with the germ, and the 

 lumen of the canal being so narrow that never more than a single sper- 

 matozoon can pass through it at one time, and the polar body being 

 budded off at the same instaut, as in Scorpcenaj JuUs^ and QrcnilabruSj 



