AND OF THE CAUDAL END OF THE SPINAL CORD. 



167 



sections, a guide-line was established by marking upon each sheet two Unes, one 

 perpendicular to the other, thus forming a series of crosses which were exactly 

 superimposed throughout the entire pile. The individual sections were then 

 plotted off on millimeter paper by fitting the crosses to a chosen perpendicular 

 line, the distance between the sections being determined by the thickness of the 

 sections and the enlargement of the drawing. The enlargements with the projec- 

 tion apparatus were as follows: Embr.yos 4 to 16 mm., X70; embryos 17 to 38 

 mm., X50; embryos 39 to 52 mm., X30; embryos 67 to 125 mm., X20. 



Table of Embryos Slwiivd. 



Length 

 (CR) of 

 embryos 



TnTn. 

 4 

 4.0 



5.5 



6.6 

 7.5 

 8.0 



9.0 



9.0 



10.0 



11.0 

 12.0 



13.0 

 13.0 

 14 

 15.5 



16.0 

 16.0 



17.0 

 17.0 

 18.0 

 19.0 

 21 



23 

 23.0 



24 

 25.0 

 26 

 26.0 

 27.0 

 30.0 

 33.0 

 33.0 

 35.0 



36 



37 

 39 

 46.0 



50 



.50.0 

 52.0 

 67.0 

 80 

 100.0 

 125.0 



Cata- 

 logue 

 No. 



836 



786 



810 



371 

 221 

 389 



422 



721 



1197 



544 

 852 



485 

 643 

 940 

 390 



406 

 43 



576 

 991 

 432 

 431 

 837 

 453 

 382 

 632 

 584a 

 1008 

 405 

 875 



75 

 145 

 211 

 199 

 449 

 972 

 362 



95 



184 



96 

 448 

 1656 

 662 

 928 

 142 



No. of somites. 



28 -|-remnant. 

 30 +remnant. 

 37+ remnant. 

 . 36 + remnant, f 

 37+ remnant. 

 38+remnant. 

 38 +remnant. 



38+remnant. 



37 



35+remnant. 



38 

 37 



37 

 37 

 36 

 35 



36 

 37 



35 

 34 

 34 

 33 

 35 

 35 

 34 

 35 

 34 

 34 

 34 

 34 

 34 

 35 

 34 

 34 

 32 

 34 

 34 

 35 



34 



35 

 34 



34 



No. of 



spinal 



ganglia. 



32 

 31 

 32 



32 

 32 

 32 



32 

 33 



33 

 33 

 33 



32 



31 

 32 



31 



31 



32 



32 



32 



32 



31 



31 



32 



31 



31 



31 



31 



31 



31 



30 



31 



30 



30 



30 



30 \ 



29 / 



29 



30 



29 



Segmental level i 

 cloaca. 



29tli so;;ment 



29th s('-.;inent 



30th segment 



Between 30th and 31st 

 segments. 



Extension of 

 caudal end of 

 spinal cord. 



Tip of tail. 



Do. 

 Do. 

 Do. 



Between 31st and 32d 



segments. 

 33d segment. 

 Between 32d and 33d 



segments. 



32d segment. 



Between 33d and 34th 

 segments. 



Between 34th and 35th 

 segments. 



33d segment 



33d segment 



3.3d segment 



33d segment 



33d segment 



35th segment 



Below last segment. . . 



35th segment 



34th segment 



34th segment 



34th segment 



34th segment. 



34th segment 



34th segment 



Below last segment. 



... Do 



... Do 



Do. 



Tip of tail . 



Do. 

 .Do. 



.Do. 

 .Do. 



Nearly to tip of tail 



Do. 

 Do. 



.Do. 



Tip of tail. 



Do.. 



Do. . 



Nearly to tip of tail 



Do 



Do 



Tip of tail 



Nearly to tip of tail. 



Tip of tail 



Do 



Do 



Do 



Below last vertebra 



Do 



Do 



Level of demarcation 



between main cord 



and its more caudal, 



atrophic portion. 



33d segment. 



33d segment. 



(?) 

 33d segment. 

 32d segment. 



Between 33d and 34th. 

 34th segment. 



32d segment. 

 32d and 33d segments. 

 31st segment. 

 32d segment. 

 32d segment. 

 31st segment. 

 Between 31st and 32d. 

 Between 32d and 33d. 

 32d segment. 

 Between 31st and 32d. 

 Between 30th and 31st. 

 Between 31st and 32d. 

 32d segment. 

 Between 30th and 31st. 

 Between 30th and 31st. 

 31st segment. (?) 

 Between 29th and 30th 

 31st segment. 

 Between 29th and 30th. 



(?) 

 Between 29th and 30th 

 segments. 



