276 ROYAL SOCIETY OF CANADA 
In the same communications we described an appearance hitherto 
unnoticed, especially striking in birds and reptiles, to which we gave 
the name “ bathychrome tissue,” while we referred to the islets of Lan- 
gerhans as “leptochrome.” With regard to this “ bathychrome”’ tissue 
we are at present very doubtful as to its significance, and the possibility 
exists that the appearance may be due to some artefact arising from the 
process of fixation. The matter will, however, be referred to later in 
the present communication. 
We shall describe the islets of Langerhans in some species of 
Ophidia and in certain of the Elasmobranch fishes, and the study of 
these new types furnishes, in our opinion, fresh confirmation of the 
general morphological views previously expressed. 
The new material was obtained in Great Britain during the summer 
of 1906, and includes two species of snake and several species of 
elasmobranchs obtained from the Marine Biological Laboratory at Ply- 
mouth. We are indebted to the Director, Dr. E. J. Allen, for his 
kindness in dissecting out and placing in preserving fluid the material 
in question. We have also to express our thanks to Professor Schafer 
for the use of his laboratory at Edinburgh by one of us (S. V.) during 
the months of May and June, and also to Professor Starling of Uni- 
versity College, London, in whose laboratory the elasmobranch material 
was partly prepared. 
THE ISLETS oF LANGERHANS IN REPTILIA. 
In addition to Kinosternon pensyllvanicum and Chrysemys picta, 
the islets of which are described in our former communication,! we 
have since been enabled to examine the pancreas of Testudo tabulata 
and Lacerta viridis and two ophidians, viz., Tropidonotus natrix and 
Coluber longissimus. 
Kee) GT ree Chrysemys picta. 
The sections show masses of hemolymph tissue clustering round 
large ducts, which are readily perceived by their staining lightly. There 
are some islets in close relation to the ductules as in the elasmobranch 
fishes (vide infra). These are especially well shown by Laguesse’s 
method D, but in our preparations the islets are certainly not com- 
mon. They are distinguishable not so much by their lightly staining 
reaction as by their capillary network, and the close packing of the 
nuclei. 
We have no further observations to offer upon Kinosternon.? 



1Internat. Monatsschr. f. Anat. u. Physiol., Bd. xxiv, 1907. 
3V. Internat. Monatsschr. f. Anat. u. Physiol., Bd. xxiv. 
