62 'Jounial of Coniparotive Nfurologv and Psychology. 



behind the points of origin of the nerves, as in the bodv buds and 

 CESophageal buds. This indicates the extent to which the ante- 

 rior-posterior spreading has dominated the developmental history. 



8. The smaller divisions of which the groups are composed are 

 usually indicated by the number of nerve rami or twigs which 

 supply the groups. The smaller subdivisions in a group usually 

 appear simultaneously, but, if there is any difference in time of 

 appearance, the anterior buds appear first. The larger groups, 

 on the other hand, are never continuous at the time of appearance 

 with adjoining groups, and never appear simultaneously. 



9. The appearance of buds in the oral and cutaneous areas 

 in detached groups spreading from anterior to posterior seems to 

 indicate the order in which specialized communis fibers reach the 

 surface through rami of the Vand VII nerves. A comparison of 

 the rami bearing communis fibers in Ameiurus with other types 

 shows a very great degree of variability in the geniculate ganglion 

 of the VII nerve as to the number of rami through which it may 

 send communis fibers and as to the time at which it sends them 

 in Ameiurus. The functional needs of the organism, such as 

 changes in the method of seeking and locating food, seem to de- 

 termine the direction of spreading and also to be more important 

 factors in determining the manner of appearance (z. e., in detached 

 groups) than the mere anatomical arrangement of trunks and 

 rami of the nerves, so that the discontinuous groups have been 

 designated as functional groups. 



LITERATURE. 



Allis, E. p., Jr. 



'89. The Anatomy and Development of the Lateral Line System in Amia calva. Jour. 



Morph., Vol. 2, No. 3. 

 '97. The Cranial Muscles and Cranial and First Spinal Nerves in Amia calva. Jour. Morph., 



Vol. 12, No. 3. 

 '00. The Lateral Sensory Canals of Polypterus bichir. Anat. Anz., Vol. 17, No. 23. 



Alcock, Miss R. 



'98. The Peripheral Distribution of the Cranial Nerves of Ammocoetes. Jour, of Anat. and 

 Phys., Vol. 33 (N. S. 13), pp. 131-153. 



Aters, H. 



'92. Vertebrate Cephalogenesis. II. A Contribution to the Morphology of the Vertebrate 

 Ear with a Reconsideration of its Functions. Jour, of Morph., Vol. 6, pp. 1-360. 



