THE ANATOMY OF THE NAUTILUS POMPILIUS 87 
tioned, which are situated at the roots of the branchiaw. The peri- 
cardium and these receptacles of the glands, when first laid open, were 
found filled with a coagulated substance so closely compacted as to 
require a careful removal, bit by bit, before the contained follicles and 
vessels could be brought into view.” 
Like Valenciennes and Van der Hoeven, I have been unable to 
find any communication between the four sacs in which the small 
double clusters of follicles are contained, and the “ pericardium ;” 
and I hold it to be certain that the other four sets of follicles are 
not contained in sacs at all, but lie free in the “pericardium” or 
posterior chamber. 
No notice is here taken of the widely different characters of the 
anterior and posterior follicles; and the figure gives both a similar 
structure. 
Valenciennes (“Nouvelles Recherches sur le Nautile Flambé,” 
‘Archives du Muséum,’ ii. 1841) pointed out the existence of three 
pairs of apertures opening into the branchial sac, besides the genital 
and anal openings; and he affirms that they open into as many 
closed sacs, which communicate neither with one another nor with 
the cavity that contains the heart. M. Valenciennes indicates the 
difference in the structure of the anterior and posterior venous 
appendages. He seems to me to have seen something of the part 
which I have described as the pallio-visceral ligament ; but I cannot 
clearly comprehend either his figure or his description. 
Van der Hoeven, in his ‘Contributions to the Knowledge of the 
Animal of Nautilus pompilius; 1850, confirmed the statement of 
Valenciennes with regard to the existence of three pairs of apertures ; 
but he showed, in opposition to him, that one of these pairs of 
apertures communicated with the pericardium. The sacs into which 
the other two pairs open are, according to this anatomist, blind. 
In the aperture of the anterior blind sac he found a concretionary 
matter which he supposed to contain uric acid, but chemical analysis 
did not confirm the supposition. Van der Hoeven refers to some 
observations by Vrolik; but as these are in Dutch, and have not, so 
far as I can find, been translated into either French, German, or 
English, I know not what they may contain. 
In his more recent essay, translated in ‘Wiegmann’s Archiv’ for 
1857, under the title of “ Beitrag zur Anatomie von Nautilus pom- 
pilius, Nan der Hoeven states that he has again found hard con- 
cretions in the chamber enclosing the appendage of the anterior 
branchial artery, and that these on chemical analysis yielded phosphate 
of lime and traces of fat and albumen, but no uric acid. 
