Miscellaneous. 159 
circulation differs greatly in its degree of intensity from the branchial 
circulation of the other Lamellibranchiate Mollusca ; itis very feeble 
or almost none; branchial injections, moreover, are rarely successful 
and always very imperfect. This deficiency of circulation depends: 
1, on the small calibre of the branchial vessels; 2, on the weakness 
of the flow of the blood, which only arrives at the branchie after 
having traversed the Bojanian and other capillary networks; and, 
3, on the existence of easy return passages, which allow the blood 
to return to the heart without having traversed the branchie. 
The mantle plays an important part as an organ of respiration. 
But during the period of reproduction it is gorged with eggs or 
spermatozoids, since it contains the reproductive organs; it acquires 
a great thickness and becomes a very active visceral organ in which 
hematosis does not take place, and in which, on the contrary, the 
blood becomes charged with carbonic acid in consequence of the 
activity of the phenomena of nutrition. The respiratory functions 
are then performed by the plaited organs, which are arranged in a 
close series on the inner surface and near the adherent margin of 
the mantle. They have been mistaken for simple vessels ; but they 
are hollow lamin, very regularly sinuous, and with very elegant 
foldings. Their cavity is rendered spongy by a true reticulum of 
very delicate elastic fibres. Their surface is clothed with vertical 
series of cells with long vibratile cilia, which effect the renewal of 
the water; the interspaces of these series of cells are occupied by 
cells with short cilia. These plaited organs receive the blood which 
returns from the mantle. I regard them as a respiratory organ, a 
supplementary branchia, destined to play an important part during 
the period of reproduction, when the mantle does not respire. This 
opinion is, moreover, in harmony with the fact that the plaited organs 
are much more prominent and much better filled with blood at the 
time when the mantle is occupied by the reproductive elements. 
These plaited organs are therefore neither a part of the corpus 
Bojani, as Siebold believed, nor simple vessels detached from the 
mantle, as has also been supposed.—Comptes Rendus, August 31, 
1874, vol. lxxix. pp. 581-584. 
Note on Herpeton tentaculatum. 
M. Albert Morice, surgeon in the French navy, has kindly com- 
municated to me that he has succeeded in bringing a living ex- 
ample of this snake to the Zoological Garden in Paris. He-ob- 
served it in the south-eastern provinces of Camboja; and writes 
as follows :— 
“ Herpeton tentaculatum is oyo-viviparous, bringing forth six young 
ones at a birth, which are 0°28 m. long. Its food is mixed; it feeds 
on tadpoles and small fish, and also on an aquatic plant called by 
the natives ‘ Ran giua,’ or Jussi@a repens of botanists.” 
A. GUNTHER. 
