4IO 



BULIyETiN OP THE BUREAU OF FISHERIES. 



On May 4 young ranging from 6 to 12 mm. in length were present in considerable 

 numbers. During the month of August, when the following observations on the eggs 

 and young of this species were made, young ranging from 6 to 30 mm. and over in 

 length were present in great abundance. It is obvious therefore that the spawning 

 season continues from April until late summer. 



Females ripe for stripping taken in August spawn relatively few ova, while imma- 

 ture ova in various stages of development are still present in the ovaries. Many females 

 which could not be stripped when taken yielded a relatively small number of mature 

 ova after being kept in an aquarium for several days. The presence in the ovaries 

 of ova in various stages of development and the relatively small number ripe for spawn- 

 ing at the same time during late summer seem to indicate that these fish spawn repeatedly 

 during the season. 



Eggs. — The mature unfertilized ova (fig. 1) are spherical in form and 1.2 to 1.4 

 nun. in diameter. Their specific gravity is slightly greater than that of sea water and 



^d£s> 



C\*PRINODON VARIEG.\TUS. 



Fig. I. — Mature unfertilized egg. X 3i. Fig. 3. — Hue with fully developed blastodisc (bd). 



they adhere in clumps, being held together by a tangle of very minute adhesive threads. 

 They are yellowish in color and highly translucent. The egg membrane is thick and 

 homy. Between it and the deUcate vitelline membrane there is a perceptible peri- 

 vitelline space. The large micropyle appears as a conspicuous cone-shaped depression 

 in the egg membrane which also causes a slight indentation in the surface of the yolk. 

 Scattered over the surface of the yolk are small groups of minute oil globules. The 

 single large oil globule contained in the yolk sphere normally rests at the upper pole. 

 Blastodisc. — The quantity of protoplasm contained in these eggs is relatively 

 large. Before fertilization the protoplasm is disposed in a layer of uniform thickness 

 investing the yolk. After fertilization has taken place this layer of protoplasm becomes 

 concentrated at one pole of the yolk sphere to form the blastodisc. The protoplasm 

 being coarsely granular in appearance, the "stre9.ming" movements toward the pole 

 of the blastodisc which occur during the process of concentration may be readily 

 observed. These "streaming" movements have been well described by Ryder" in 

 the eggs of the cod and more recently by other investigators in the eggs of other species 

 of teleosts. 



« Ryder, J. A.: Embryography of osseous fisbes. Report, United States Fisll Commissjon, 1882, p. 455-605. 



