Jordaii (1905) reported that "A. Lkieller, in 1365. shovred that 

 all Ox the ova in the lamprey WGre of the sane sizej and that 

 after spai/vningj no small reprod'active bodies remained to be devel- 

 oped later." It is not quite clear to which species he has refer- 

 ence. In the light of tlae eiia-nination of this and subsequent 

 specimens of the sea latnprey, this statement is in need cf quali- 

 fication. Three categories of ova i^ers present in the material 

 examined. First, there are the developing ova (represented by 

 the highest modes in Figure 2U). Tliese are by far th3 most nu- 

 merous in the ovary and are the eggs which are destined to be 

 spawied very shortly. Second, there are ova of apparently retarded 

 develoixient Tirhich I term "partially developed ova" (these are 

 represented in Figure 2lj. by each lor; m.ode to the left of the high 

 ones representing the developing ova). The partially developed 

 ova are scattered throughout the ovary and differ from the larger 

 ones onlj'" in size and amount of contained j^'ollc; the form appears 

 similar. Such eggs are present in variable numbers in all females 

 but are more coi'nmonly found in the smallest specimens and are 

 quite infrequent in the larger ones. The individual represented 

 in Figure 2l|. is believed to have contained the largest number of 

 partially developed ova in the entire series studied. It probably 

 represents the greatest proportion of this Icind of eggs present in 

 the females of an averag-e spavming run. In examining females in 

 "'A'hich the eggs had burst into the coelom, I found that some cf 

 these retarded ova were extruded ivith the fully developed ones. 

 The majority, however™ remained trapped in the remnants of the 

 ovary. Other e^cperirnents have shot-Ti that those retarded eggs that 

 are extruded Tdth the mature ova can become fertilized but it is 

 not knoim if full development to hatched larvae occurs. Ova in the 

 third category are microscopic in size, generally between 0.20 and 

 0.30 millimeters in diameter. They are variable in number in dif- 

 ferent females, but as a rule they are quite numerous although 

 their total number is always less than that of the more mature eggs. 

 Tliese ova, unlike those of the other two categories, are translucent, 

 contain little or no yoUc, and are still firmly attached to pedicles 

 in the gonad. Since they could readily be found only in the frayed 

 ovarian tissue of spent females, they do not enter into any of the 

 measurements or counts that were made. They were too small to be 

 seen vri-th the mignification used in making the counts and measiiT'e- 

 monts of the other two kinds of eggs. It seems logical to conclude 

 lor the sea lamprey that mature ova develop at the e:cpense of the 

 retarded and undeveloped ones and/or that some mechanical impedi- 

 ment aborts the development of the latter. I do not believe that 

 cither of the latter categories could be construed to represent a 

 potential reserve stock that would enable the female to spaT>n again 

 in the follov/ing year. 



Jordan (1905) further states that "....the most careful mdoro- 

 ;:copical examination of ovaries or testes has failed to reveal any 

 evidence of new gonads or reproductive bodies." I.^'' prelirainar;,'' 

 examinations seem to confirm this, l^lven if it _ should be demonstrated 



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