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Early stages in the development of cymatogaster.* By Carl II. Eigen- 



M A N X . 



The investigation of which this is an abstract has been conducted with 

 various intermissions since December 1888. I present here simply the 

 result. The proof for any one of the propositions would take up more 

 than the time allotted for all of them. The details with all necessary fig- 

 ures will be published during the year by the U. S. Fish Commission. 



A large per cent, of the California fishes bring forth their young alive. 

 The members of one family of these fishes, the Scorpasnidse, bring forth 

 many thousands of young in a very immature condition. The members of 

 the other family, the Embiotocidse, bring forth comparatively few young, 

 3-80, but these are sometimes an inch or two in length and resemble the 

 parent as much as the new born mammal resembles its parent. It is this 

 family which is of great interest and to which I devoted most of my time. 

 After examining many of the species just before and during gestation I 

 selected Cymatogcuster for a special study, because the peculiarities have 

 become most marked in this species. The results are as follows : 



1. Copulation takes place in July. This statement is based on the fact 

 that the testes of the male are very much enlarged at this time and on 

 the fact that the ovaries from now on are filled with spermatozoons. The 

 act of copulation has not been observed. 



2. The secondary sexual differences are considerable— among them 

 may be mentioned a small gland or bag on either side of the anal of the 

 male. From it extends a papilla forward to beyond the anterior margin 

 of the fin. 



:*>. The spermatozoa have a long rod-shaped head in place of the 

 globular one usual in fishes. 



4. The spevmatozoa remain dormant in the ovary till December 

 when they become exceedingly active. 



5. The eggs mature and are fertilized between November 1st and Febru- 

 ary 1st, the largest fishes maturing the eggs earliest, the next in size a 

 little later and the smallest individuals last. 



t>. Those spermatozoa not utilized in fertilization remain in the ovary 

 for several weeks longer. They are finally eaten by the larva' when the 

 digestive tract of the latter has been sufficiently developed. 



7. During the early stages of gestation the females remain in shallow 



- I have hitherto referred to this lish as Micrometrus. A re-examination of the litera 

 ture bearing on the subject proves that this name is not available. 



