301 



recognize it in embryos of 12, 18, 18. 24, 26, 40, 120 mm. From 

 this it follows that it is not infrequently absent. In some embryos the 

 portion of the planum scapulae cranial to tiie foramen, i.e. Rutherford's 

 praescapula, made an angle with the rest of the plannm, a fact that lends 

 support to Rutherford's view, viz thai it is really a separate piece 



Fig. 3. Homo 25 mm. transverse. 5c = Scapula; 

 Acr = Processus acromialis. 



of cartilage. The foramen which, in yonng embryos, is sitnated 

 rather closely to the margo superior, as observable in fig. 3, migrates 

 in older embryos towards the margo verlebralis. Conseqnently Ruthkr- 

 fohd's praescapula is relatively enlarged. 



Now it is an interesting fact that this foramen does not occur in 

 any other mammal, neilher in reptiles, nor in amphibians. Al leasl 

 1 never detected any. The following embi'yos I have examined for 

 the occurrence of this foramen. 

 » Semnopithecus manrus 20 mm. (C. R.) 



IMacacus cynomolgus 17 mm. (C. R.) 



Cercopilhecus 2 stages. 



Sns scrofa N. T. (Keibel) 83—85, N. T. 88, N. T. 88, N. T. 91, 

 24 mm. (C. R.) 26 mtn. (C. R.) In the last two embryos two 

 foramina were recognized in the fossa infraspinata. It is not quite 

 impossible that these foramina are aiialoga of the foramen in the 

 liuman shonlder-hlade. 



Bos taurns 21 mm. (C. R.) 



Ovis aries 19.5, 20.5, 21.5, 22.5, 23, 23.5, 26, 27, 29, 35, 

 45 mm. (C. R.) 



20* 



