28 



The second point that I mention, and the one of most interest, is 

 the presence of a band of high epithelium in the floor of the oeso- 

 phagus, beginning near the mouth and extending the entire length of 

 this portion of the digestive tube, A similar band on the floor of the 

 stomach is found in other species, and is also well developed here. 

 Whether the two bands are in reality but two parts of one band, I am 



not certain. As in other species 



^■s- 2- so here there is an annular thi- 



^.„-'-s y^\. ckening of the wall of both the 



"/^Ç^"''~\ \( ^y\ \ oesophagus and the stomach at 



in....i .h>x ^— ^ ^ ^-^ the junction of the two, and both 



\ '•■■'''J?%X (l 1 ^^^ ventral longitudinal bands 



ae. n \\ ^ /T^^^^-^ y merge into these ; but Avhether they 



// Mi /^\\v\ ^^'® ^^ ^^ regarded as passing 



// M ^\ %K \V\\ through it to become continuous 



' ' ' ' Cy'' W' '^^^ ^ \\V\ with each other, I have not been 



, 7 \\JÉ^i ^^ I able to decide. It is certain, howe- 



fl?.(5.--\ .\ ^^^/ y^^" / • 



V [ ' "x^ ^^Ê ^^^^ ^^^^^ there is some difference in 



S.è^^^-L -y'^^^V structure between the oesophageal 



/ \ 0^ ( ( and the gastric bands. The most 



\y g ---1---..$'. marked of these differences is in 



[I i // the character of the cilia found on 



i\ I ( each, those of the latter being 



Transverse section of the Tornarla shown much longer and heavier. Indeed, 



in fig. 1 (see text for statement concerning I am in some doubt about the 



the position of this section), c? cilia on «le presence of cilia on the oesopha- 



esophageal band, ec ectoderm, oe Oeso- i -i j 4. n t^ ^i, 



, ^ '' , , n ,. , . , . , 1. . seal band at all. It they are pre- 

 phagus. oe.o band 01 thick epitheuum m ni 



floor of oesophagus, m anterior border of «^nt they are s^ery small , and are 

 mouth, s Stomach, s.h thick epithelial much obscured by some kind of 

 band in floor of stomach. a secretion that does not seem to 



be found on the gastric band. 

 Furthermore there is a difference in the cells of the two bands, those 

 of the gastric band being rather larger and more distinct; their nuclei 

 appearing in the sections considerably less crowded. The points dis- 

 cussed in connection with the structure of the two bands are illu- 

 strated in fig. 2, which is reproduced from a drawing made by the aid 

 of an Abbé camera lucida. The specimen from which this series of 

 transverse sections , of which this represents one , was made , had be- 

 come somewhat flattened dorso-ventrally in killing, but the series is 

 complete and there is no difficulty in identifying the several parts in 

 their relation to one another. Owing to the upward direction taken 

 by the first portion of the oesophagus, a cross, though somewhat obli- 



