246 THOMAS DVVIGHT OX 



of normal 2d, witli no contact between the cartilages, snppression of a thoracic (or cervi- 

 cal) vertebi'a. 



Class I. 



Tiiis class comprises the spines in which there is the normal number of praesacral 

 vertebrae, but in which there is some irregularity of the costal element at the junction of 

 the thoracic region with the loins or with the neck. The former cases are in Group A. 

 the latter in B. 



The following spines are in Class I. Group A: 615. G-19, 636, 567; Group B : ]. 

 A-30, 649, 729, 306. 



Groiqj A. 



The peculiarities of this group are so common that it might have been enlarged in- 

 definitely. Either the costal element of the last thoracic vertebra (19th) is too small, or 

 that of the ne.xt below it is too large. 



615. Cat. 9379-4.' 



Female, white, aet. 63. Vertebral formula : C. 7, T. 12, L. 5, S. 5, (C. 4?). 



This is the slightest possible deviation from the norm. The only peculiarity is that 

 the last ribs are \ery small, and, though doubtless oi-iginally distinct, are now fused wdth 

 the 19th vertebra. The length of the right one is 3.5 em., and of the left 2.6 cm. The 

 spread of the lumbar transverse processes is normal, increasing to the 3d. The 4th sacral 

 IS a penultinuite. The change of the articulai- processes between back and loins occurs 

 normally. Tliei-e is nothing irregular or transition;d in the sacrum except that only two 

 vertebi-ae articulate with the ilium. Tlie conjagata vera is at the 3d sacral, near the top, 

 The pieces of the coccy.x are fused, and their numljer is uncertain. 



1 The fii-st immbev is that u.sed in the dissectiiig-roum, the hitter the one put on when the specimen is entered in the cata- 

 logue of the Museum. I always refer to a specimen under the former number, as it is tiie t.ue under which I have studied it. 

 .Vs both numbers are kept im the s]ieeimen card there is no difficulty in using either. 



