194 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



endeavored to solve the problem whether oysters already produce young 

 ones during the the first year of their life, and he found among 435 one- 

 year-old oysters 35 which had spawn in their branchiae, 127 which had 

 eggs in the ovaries, and 189 having spermatozoa; there were, therefore, 

 only S4 which during this first year did not show a pronounced sexual de- 

 velopment. (It remains to be seen whether the oysters containing eggs 

 or speimatozoa would exercise the sexual functions during the year 

 when the investigation was made.) Professor Mobius* examined 300 

 oysters taken on May 25, and found IS per cent in a stage of sexual 

 development approaching one of the two sexes, while of the remainder 

 (S2 per cent) one half contained eggs, and the other half spermatozoa. 

 He does not state what method he pursued, whieh is to be regretted, 

 because the value of the results obtained depends entirely on this 

 method. I have, therefore, deemed it necessary to follow the somewhat 

 difficult method described below. 



First of all I ascertained the age of every oyster that I examined, and 

 noted at the same time whether it had been taken from a tile, from a 

 shell, or from a stoue. I gave a number to each oyster, while a piece of 

 each was put in alcohol for further examination. Later I took a small 

 fragment of each piece and stained it, for microscopic examination. 



The oysters examined by me were opened between the 10th and 28th 

 of June, and as the piece taken from each was immediately put in alco- 

 hol, my examination enabled me to judge of the condition of the sexual 

 organs on the day the oysters weie opened. I must confess that the 

 preparation of a similar fragment frequently did not answer the purpose 

 aud did not always .yield a decisive result. Some oysters had spawn in 

 the beard ; they had exercised the functions of females in the course of 

 the year. Others contained a large number of mature or nearly mature 

 eggs, and would have deposited these eggs in a few days during the 

 following month or later.t Others again contained mature or nearly 

 mature spermatozoa; they evidently were going to participate in the 

 spawning process during the season. On the other hand, oysters con- 

 taining young cells producing eggs, and mother cells of spermatozoa, 

 possessing, therefore, the two elements in a rudimentary state of de- 

 velopment, are in a stage when it is extremely difficult to ascertain 

 whether they will take part in the spawning process of the season, and 

 what their function will be. According as the male or female element 

 seemed to prevail, I determined them as being inclined to become either 

 males or females. There were finally some oysters (their number was 

 not very large) whose sexual organs were but little developed; it was 

 impossible to state with certainty if these oysters had already per- 

 formed sexual functions, or whether they were in a sick or feeble con- 



*Karl Mobius: "Die Ausler und die Amternwirih8c'haft i ,> Berlin, 1877, Wiegandt, 

 Ilempel, & Farcy. 



t There is no doubt that the temperature of the -water either accelerates or retards 

 the spawuiug process. 



