4^6 Grorgt' L. Stnrtn; M.D. 



of it can be seen in model a. The acoustic nerve and ganglion are 

 attached to the median and ventral surfaces of the labyrinth, and 

 the nerve connection w^ith the brain appears to be normal. 



The conditions found in the three specimens pictured in Fig. 2 

 are typical of what is found in the other five specimens examined. 

 They vary in the completeness of their differentiation, some of 

 them consisting of only a vesicle with perhaps a single canal pouch, 

 but in all cases the acoustic ganglion is present on the ventro 

 medial surface, and the macular areas can be recognized. The 

 lagena is present in seven out of eight cases. The endolymphatic 

 appendage developed in six out oi eight cases. As regards posture, 

 the rule is that the more perfectly the labyrinth is developed the 

 more accurately its posture corresponds to the normal relations. 

 But even in the most imperfect specimens when the endolym- 

 phatic appendage appears it is on the medial surface, and the ten- 

 dency to canal formation is always on the dorso-lateral surface, 

 and the saccule and lagena appear on the ventral surface. This 

 condition of course applies only to vesicles that have been im- 

 planted in the acoustic region as was done in all the above cases. 



Rotation in One Direction. In four experiments the ear vesi- 

 cle was rotated i8o° around its vertical axis, i.c, turned face inward. 

 These specimens were then reared as in the preceding instance, 

 and eventually cut in serial sections. A reconstruction model of 

 one of them is reproduced in Fig. 3, and if it is compared with 

 Fig. I it will be seen that although the vesicle was started in its 

 development with invaginated side toward the brain yet the com- 

 pleted labyrinth has the normal posture. A section of the same 

 specimen is reproduced in Fig. 4, showing the labyrinth surrounded 

 by developing cartilage. The acoustic ganglion is connected 

 in normal manner with the brain and sends peripheral fibers to 

 the thickened floor of the saccule. The endolymphatic sac is in 

 its normal position, and the narrow duct can be seen connecting 

 it with the main chamber of the labyrinth directly median to the 

 crus commune. The series through this specimen show that his- 

 tologically it is practically perfect. Of the other three specimens 

 one was almost equally perfect, another showed some abnor- 

 malities in the formation of the canals and the lagena, and the 



