28 THE AMERICAN MONTHLY [ February, 
In Cardium edule the organ is described in full, and others are compared 
with it. Its parts are:—1. ‘ The cavity of the byssus,’ a large space in the 
centre of the keel of the hatchet-shaped foot. 2. ‘ Zhe canal of the byssus,’ 
opening on the surface by a pore. 3. ‘ The byssus,’ a hyaline thread running 
out from the cavity through the canal. 4. ‘ Byssal glands,’ glandular cells 
lying below the epithelium, and opening separately into the cavity. 5. ‘The 
groove’ running forward from the canal along the margin of the foot to the 
anterior end. 6. ‘ Glandular cells of the groove’ opening into it among the 
epithelium cells. The epithelium is everywhere perfectly continuous, and in 
the cavity is thrown into numerous lamellar folds. , 
Various departures from the plan are described and figured ; there may be 
no functional byssus, but the other parts may all be present, or the groove, or 
the glands, or even the cavity may be wanting, or there may be in the adult 
no trace of any of the organs. In the same family, or even genus, wide varia- 
tions may occur. Thus 7apes virginea has no functional byssus, the cavity, 
glands, and lamellz are present, while in Vezws rudzs and others of the family 
no trace of the apparatus remains. In Axomia ephippium the ossicle by 
which the animal is attached is a true byssus, formed in a cavity lined with 
lamelle, a precisely similar one being present in the foot of Arca tetragona. 
The anomalies of its relation to the parts of the body are explained by the 
lateral attachment of the creature. The ‘ corzet’ of Anomia, with its groove 
leading to the byssal cavity, is similar to the muciparous gland on the anterior 
part of the foot of Pecten maximus. In Unio and Anodonta a cavity in the 
keel of the foot is the only remains of the byssal organ in the adult. This, 
doubtless the water pore of Kollman, Griesback and others, is lined with 
continuous epithelium. It is to be regretted that lack of material has pre- 
vented research into the embryonic condition of many of the retrograde forms. 
Barrois also describes as characteristic of the lamellibranchs special mucip- 
arous glands in the anterior portion of the foot; these, in some cases, line 
the inside of a cavity, e..o., Pecten maximus; in other cases, the organ being 
everted, they line the outer surface under the epithelium of a pedunculated 
club-shaped body, e. 2., Luctna lactea. The view that the byssus of the 
lamellibranchs is homologous with the gastropod operculum is rejected on 
anatomical and histological grounds, and the muciparous byssiparous glands 
are thought to correspond with the ‘ Lippen-driisen’ and ‘* Fusshéhledrtisen ’ 
of Carriere, the one upon the fore-end of the gastropod foot, the other upon 
the creeping surface. 
The second portion of the work is a full historical and critical review of the 
‘ water-pore’ controversy. No new observations of importance are recorded, 
and the position maintained by the writer is the same as already represented 
in this journal (see vol. iii, p. 130).— Henry Leslie Osborn, American 
Naturalist, Dec., ’86. 
MICROSCOPICAL TECHNIQUE. 
A new settling tube for urinary deposits. By Frank Vanderpoel. 
It is often found necessary in the microscopical examinations of sediments 
contained in liquids—notably so in the examinations of urinary deposits—to 
make use of a settling vessel of such a shape that the deposit, in finding its 
way to the bottom, shall be caused to gravitate toward a small central spot, 
whence it can be afterwards removed by means of a pipette. For this pur- 
pose conical test-glasses and test-tubes ‘on foot’ have been devised, and have 
found a very extended use. 
They have one objection, however, namely, that in order to get any of the 
sediment into the pipette, and keep it all there while the latter is being with- 
