556 



Bashford Dean Memorial Volume 



TABLE I 

 SIZES IN MILLIMETERS OF UTERINE EMBRYOS AND EGGS 



Ho. 



Embryo 



ro\\Sac 



Where 



1 



170 



72x68 



Columbia University 



2 



175 



92x90 



Figure 11, plate I 



3 



180 



77x75 



Columbia University 



4 



210 



75x57 



Am. Mus. of Nat. Hist. 



5 



210 



85x66 



Mus. of Comp. Zool. 



6 



245 



74x60 



Am. Mus. of Nat. Hist. 



7 



305 



83x57 



" '' 



8 . 



320 



76x64 



" " 



9 



327 



67x55 



Columbia University 



10 



331 



111x100 



Dean's Notebook 



11 



374 



73x51 



Am. Mus. of Nat. Hist. 



12 



390 



100x70 



Figure 49, plate V. 



Just here it should be recorded that in Dean's notebook on the page of his list of 

 specimens to be drawn is this entry. ''Bt. in Tokyo June 20: 317; 331, yolk sac HI x 100; 

 352; 390, yolk sac 100 x 70; 4 embs. large taken about May 1, 1905. 8 in fecaale". I judge 

 that the ''4 embs. large" refer to the four for which he gives sizes, that they were taken 

 from the female captured May 1, that they were preserved, and that he purchased them 

 June 20 in Tokyo. This seems pretty certain. Possibly they were 4 of the "8 in female" 

 as noted. Judging by their close gradation in sizie, I conjecture that they came from one 

 uterus. If so, one can judge the tremendous distention of this. But what if one uterus 

 contained "8" such embryos and eggs! It seems almost unthinkable, yet Nishikawa 

 (1898) says ''The right oviduct is very much distended and contains from 8-12 eggs. . . . 

 The limits observed in seven specimens." 



Two of the specimens recorded in the table were drawn for Dean and are reproduced 

 in the plates. In Figure 11, plate I, the embryo measured 175 mm. and the yolk 92 x 90 mm. 

 Still more striking is the colored Figure 49, plate V of a fish 390 mm. (15.35 in.) long on 

 a yolk sac which measured 100 x 70 mm. Let the reader imagine (if he can) 8 to 12 embryos 

 and yolk sacs of this size in the uterus of even a 1960'mm. female (the largest Chlamydo- 

 selachus on record). The egg and embryo of the colored figure are in our collection here, 

 and the fish in its jar of alcohol looks even larger than it does when portrayed in its 

 natural colors. 



As one studies this table, three things attract attention. The first is that there are 

 several discrepancies in the sizes of the yolk sacs in proportion to the sizes of the little 

 fish found thereon. Surely some of the discrepancies date back to the varying sizes of 

 eggs in the ovary. There must be more variability in the size of mature eggs in the 

 oviduct than has heretofore been thought. The next idea is that the period of gestation 

 must be very long to give time for the resorption of these great yolks, and then that the 

 young fish when ready for extrusion must be from 20 to 25 in. long. The matter of 

 the long period of gestation (surely at least 2 years) has been treated earlier. 



