112 MERISTIC VARIATION. [part i. 



'Id. Male, in Cambridge Univ. Mus., No. 78. Preparation shews 

 C 7, D 11, and the 19th vertebra formed as the 1st lumbar: re- 

 mainder not preserved, but Professor A. Macalister kindly informs 

 me that there were 5 lumbars and 5 sacrals, giving C 7, D 11, L 5, 

 S 5. The 7th vertebra has cervical ribs, the left being large aud 

 articulating with a tuberosity on 1st thoracic rib, the right being 

 considerably smaller, but now broken at the end. Only 11 pairs 

 of thoracic ribs. Change of articular process from dorsal to lumbar 

 begins partially on the left side between 17th and 18th vertebra 

 (instead of between 19th and 20th) and is complete on both sides 

 between 18th and 19th. The 19th bears no rib. [Backward 

 Homceosis, greater on left side than on right, as seen in the 

 greater size of the left rib on the 7th vertebra, and in the change 

 of processes beginning at a higher level on this side. As the 

 coccyx is not preserved it cannot be seen whether there is one 

 segment less in the whole column, which would be the case were 

 the backward Homceosis complete.] 



20. Female, cet. 40. C 7, D 12, L5, S 6, C3. The 7th vertebra bore 

 cerv. ribs, free on left, ankylosed to vertebra on right. Change of 

 artic. processes partially on left side between 18th and 19th (instead of 

 between 19th and 20th). Twelfth thoracic ribs short, being 1^-in. long 

 on left, If in. on right. Struthers, J., J. Anat. Phys., 1875, pp. 53 

 and 35. [There is therefore backward Homceosis, greater on the left 

 side than on the right.] 



21. Vertebrae C 7, D 11 or 12, L 5 or 4, S 6, C lost. Eleven pairs of ribs. 

 The 19th vertebra having a transverse process on the left side re- 

 sembling that of the vertebra next below it, as regards place of origin 

 and its upwaixl slope, but is longer than it by ^ in. and is nearly a 

 third broader and also thicker. On right side corresponding part is in 

 two pieces. Change of articular pi'ocesses complete between 18th and 

 19th (instead of between 19th and 20th). The 21th vertebra is united 

 to sacrum, but is of unusual shape, differing gi-eatly from a normal 

 1st sacral (25th vertebra). The 29th vertebra is nevertheless not 

 detached from sacrum. Struthers, /. c, pp. 70 and 57. 



22. Adolescent subject. 7th cervical, 12 dorsals and ribs, and 3 lumbars 

 preserved. 11th ribs reduced, 4 in. long, 4^ in. with cartilage. 12th 

 ribs rudimentary, left 1 in., right f in. long, breadth of each about |Tn. 

 Artic. processes change chiefly between 18th and 19th vertebrae. 

 Struthers, I. c, p. 55. 



23. Male, cet. 47. C 7, D 12, L 5, S 5, C 4. Twelfth ribs very unequal; 

 right scarcely 2 in., left 3^ in. The 5th lumbar ankylosed to sacrum 

 by its right transverse process. Struthers, 1. c, p. 57. [Backward 

 Homoeosis on right side in respect of reduction of 12th rib and union 

 of 24th vertebra to sacrum on that side.] 



B. Forward Homoeosis. 



As was remarked in the case of backward Homceosis, if each 

 vertebra were to be developed in the likeness of the one which in 



