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MESSRS. E. M. BALFOUR AND W. N. PARKER ON THE 
fig. 61, pi). It then has the form of a funnel-shaped diverticulum of the dorsal 
wall of the duodenum, immediately behind the level of the opening of the bile duct, 
hrom the apex of this funnel numerous small glandular tubuli soon sprout out. 
The similarity in the development of the pancreas in Lepidosteus to that of the 
same gland in Elasmobranchii is very striking.* 
The pancreas at a later stage is placed immediately behind the end of the liver in 
a loop formed by the pyloric section of the stomach (Plate 27, fig. 62, p,). During 
larval life it constitutes a considerable gland, the anterior end of which partly envelopes 
the bile duct (Plate 27, fig. 63, p.). 
Considering the undoubted affinities between Lepidosteus and the Teleostei, the 
facts just recorded with reference to the pancreas appear to us to demonstrate that 
the small size and occasional absence (?) of this gland in Teleostei is a result of the 
degeneration of this gland ; and it seems probable that the pancreas will be found 
in the larvae of most Teleostei. These conclusions render intelligible, moreover, the 
great development of the pancreas in the Elasmobranchii. 
We have first noticed the pyloric caeca arising as outgrowths of the duodenum in 
larvae of about three weeks old, and they become rapidly longer and more prominent 
(Plate 27, fig. 62, c.). 
The portion of the intestine behind the vitelline duct is, as in all the Vertebrata, at 
first straight. In Elasmobranchs the lumen of the part of the intestine in which a 
spiral valve is present in the adult, very early acquires a more or less semilunar form 
by the appearance of a fold which winds in a long spiral. In Lepidosteus there is a 
fold similar in every respect (Plate 25, fig. 53, sp.v.), forming an open spiral round the 
intestine. This fold is the first indication of the spiral valve, but it is relatively very 
much later in its appearance than in Elasmobranchs, not being formed till about three 
weeks after hatching. It is, moreover, in correlation with the small extent of the 
spiral valve of the adult, confined to a much smaller portion of the intestine than in 
Elasmobranchii, although owing to the relative straightness of the anterior part of the 
intestine it is proportionately longer in the embryo than in the adult. 
The similarity of the embryonic spiral valve of Lepidosteus to that of Elasmobranchii 
shows that Stannius’ hesitatation in accepting Muller's discovery of the spiral valve 
in Lepidosteus is not justified. 
J. Muller (‘Bau u. Entwick. d. Myxinoiden ’) holds that the so-called bursa entiana 
of Elasmobranchii (i.e., the chamber placed between the part of the intestine with the 
spiral valve and the end of the pylorus) is the homologue of the more elongated 
portion of the small intestine which occupies a similar position in the Sturgeon. This 
portion of the small intestine is no doubt homologous with the still more elongated 
and coiled portion of the small intestine in Lepidosteus placed between the chamber 
into which the pyloric caeca, &c., open and the region of the spiral valve. The fact 
that the vitelline duct in the embryo Lepidosteus is placed close to the pyloric end of 
* Vide E. M. Balfour, ‘ Monograph on Development of Eias mob ranch Fishes,’ p. 226. 
