May 26, 1899.] 



SCIENCE. 



741 



time or place of spawning of the eel in 

 American waters, and I wish, therefore, to 

 present a brief note on the only instance of 

 a spawning eel which has, up to the pres- 

 ent time, come within my notice. I had 

 hoped to give further instances relating to 

 this matter, but I have, unfortunatelj', been 

 unable to secure additional data. 



The general interest I have always had 

 in the spawning of the eel has led me, from 

 time to time during the past twenty-five 

 years, to examine the condition of the 

 ovary in numbers of specimens which have 

 been brought to the New York markets 

 during various seasons. The eggs which 

 I have, however, noticed in this material 

 were never larger than some which I 

 observed twenty years ago in the so- 

 called 'eel-fat,' that is to say, minute 

 ovarian eggs, measuring possibly .03 mm. 

 in diameter. It has long been known, in a 

 general way, that in this neighborhood the 

 eels are usually taken in great numbers dur- 

 ing November and December, at the time of 

 their passage seaward down the Hudson or 

 in Gravesend Bay ; and it has always been 

 supposed that the spawning takes place 

 within a month or so of this time, since in 

 the earl j^ spring the elvers (?)io)!i(Jes), which 

 ascend the rivers, are found never measur- 

 ing less than two inches in length. That 

 the actual spawning-time, however, may be 

 a much later one, seems to me now more 

 than probable for the following reason : On 

 May 8, 1898, my attention was brought 

 to an eel containing ova which separated 

 readily from the ovary and filled the cavity 

 of the abdomen, and I am able to give the 

 following notes relating to this very un- 

 usual specimen. I find it was taken at At- 

 lantic Highlands by Lewis Morris, in rela- 

 tively shallow water, between two and 

 three fathoms, in a locality which is well 

 known as an eeling ground. The color of 

 the specimen was relatively bright, but not 

 unusually so, nor waa the eye notably 



larger than in similar specimens from the 

 same locality. The specimen was rela- 

 tively small, measuring 42 cm. in length, 

 and weighed but 135 grammes. The eggs 

 are .4 mm. in diameter. A microscopic ex- 

 amination of the ova made by my friend, 

 Professor Dean, of Columbia University, 

 shows that the germinative vesicle is clearly 

 defined, and that the egg is all but ma- 

 ture. The ova, as I have already noted, 

 are readily shaken free from the ovarian 

 tissue. 



The distinct interest of this observation 

 appears to be this, that the eel may, in ex- 

 ceptional instances at least, ripen its eggs 

 in relatively shallow water, possibly in the 

 inlets of many of the bays and sounds, in- 

 stead of at the great depths which the 

 European observers have hitherto regarded 

 as necessary for sexual maturation. As far 

 as I am aware, the only instance of the tak- 

 ing of a sexually matured eel has been in 

 waters of one hundred or more fathoms in 

 depth. In all these instances, moreover, 

 the female eel has been of considerable size, 

 at least half again as large as the present 

 example. 



The present specimen, moreover, gives 

 us a clue to the spawning time of the eel in 

 our neighboring waters ; in any event, it 

 demonstrates that here the season of ovula- 

 tion, during the month of May or there- 

 abouts, is certainly many months later than 

 in the Mediterranean, for in the latter 

 locality, according to Grassi and Calan- 

 druccio (Fischei-ei Zeitung, XXII., 428), the 

 eggs can only be found between the months 

 of September and January. I should note, 

 however, that the possibility is not ex- 

 cluded that the present eel was of excep- 

 tional sexual characters, like the small ex- 

 amples of shad showing almost ripened 

 eggs which are sometimes taken one and 

 even two months in advance of the regular 

 ' run.' 



Eugene G. Blackford. 



