122 BRAIN AND BODY OF FISH 



arranged in two rows on each side of a central raphe, upon which 

 the two rows are folded longitudinally so as to form a lining to the 

 ■olfactory tube." It is interesting to note when we consider the 

 important part the olfactory system plays in the feechng habits of 

 both eels and soles, that the sole has a similar arrangement of its 

 olfactory plates, but the raphe in the sole is depressed so as to form 

 a, groove from which the plates rise up. It will be noted how 

 intimate the functions of smell and taste are in the eels. 



In anguilla, taste-buds are present on the tongue and lips and on 

 the skin of the anterior tubular nostril. A section across the medulla 

 of the eel will show that the large facial nerve passes in a transverse 

 direction to end in a large facial lobe on either side, and this oval- 

 shaped area makes a slight bulge into the rhomboid fossa ; however, 

 it does not appear on the siu'face, being completely covered by the 

 overlying somatic-sensory lobes. Nevertheless, the facial lobes 

 extend a considerable distance in an antero-posterior direction. 



It may be recalled that the sole has a minute facial lobe and that 

 taste-buds are absent ; but there is a well-marked central acoustic 

 lobe. In describing the complex cerebellum of the eel, we shall 

 have occasion to refer to its acoustic area. As an earlier study of 

 the cerebellum of the eel disclosed several interesting and suggestive 

 details in connection with its relations to the acoustico-lateralis 

 lobes, I have re-examined the serial sections and made a series of 

 drawings under low jDower by the help of a Leitz projector. Plate 24 

 is a section across the commencement of the acoustic tubercles, and 

 the cerebellum is seen overhanging the prominent fifth lobes of 

 the medulla. Fig. ii is a section across the most prominent 

 portion of the acoustic tubercles which are here both broad and 

 deep ; the superior extremity of the large-celled area on either side 

 curves medially and merges with the stratum granulosum of the 

 cerebellum, which does not extend across the middle of the cere- 

 bellum as is usual among the teleosteans, but is divided medially ; 

 the result is that two sigmoid areas are formed, facing each other, 

 and formed by the large-celled tissue of acoustic tubercles and the 

 stratum granulosum of the cerebellum. The stratum gi'anulosum 

 extends right up to the lateral margins of the cerebellum and in 

 the middle line there is a narrow band of stratum moleculare 

 separating the two sigmoid areas. In this section there can be 

 seen a small group of cells on either side representing the central 

 acoustic area of other fish ; it is necessary to note this, as it is said 

 by some observers that an eel can grunt, and therefore we would 

 expect some indication of an acoustic area. Fig. iii is a section still 

 further forward where the acoustic tubercles have ceased to be 



