ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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there arise (1) a fine connective which, after a more or less long course, 
fuses with the cerebro-visceral connective ; (2) a series of fine nerves 
which pass to the gill of their own side ; (3) a nerve-trunk which 
fuses with the branchial nerve, and gives off fine branches to the median 
part of the gill, and (4) a prolongation which, by union with other nerves, 
forms a large-meshed network. 
Gadinia peruviana.* — Dr. L. Plate has had the opportunity of 
finding a number of this Gastropod on the coast of Chile. The mantle 
forms a circular fold around the whole body, as in Patella , and is 
divisible into a central smooth zone, and a peripheral zone which is rich 
in glands. The opening of the air-space can be closed by a sphincter, 
when the animal goes under water. From before backwards there follow 
one another the mantle-cavity, the kidney, part of the gonads, and the 
liver with a few intestinal coils. The first of these is asymmetrical 
in form, and has the kidney in its roof ; anteriorly this roof widens out 
as a delicate membrane, but has no aggregation of blood-vessels. The 
kidney has a large cavity in its interior, and on its walls there are a 
number of villi and folds, which produce a spongy appearance. There 
is no special ureter, the urine being emptied into the commencement of 
the respiratory duct by a small papilla. 
The pharynx, which is elongated, has no jaw; the teeth of the 
radula are extraordinarily delicate and small. The oesophagus is re- 
markable for having opening into either side of it, posteriorly, a sac 
2 mm. long ; these would appear to be salivary glands. There is no 
sharply defined stomach. The animal is a vegetable-feeder. 
The seven centres of the nervous system are easy to demonstrate, as 
all the commissures are distinctly developed. The central ganglia are 
connected by a long commissure. The two small buccal ganglia are 
easily overlooked, as they lie deep in the wall of the pharynx. The 
hermaphrodite gland, which is large, is composed of a number of vesicles 
loosely connected with one another ; the copulatory organ is a simple 
muscular tube without glands or stimulating apparatus. 
The author thinks that Gadinia is not a Pulmonate Gastropod, but 
an aberrant Opisthobranch which has lost its gills, and breathes by its 
integument. 
Anatomy and Physiology of Ancylus lacustris and A. fluvia- 
tilis.j* — M. E. Andre finds that the muscular system of these Molluscs 
is only slightly differentiated ; there are two columellar muscles. The 
renal organ is said to be quasi-embryonic in character. There is no 
pulmonary cavity, nor any organ specially adapted for respiration ; this 
process is largely effected by the pallial pad, and slightly by the auriform 
lobe. This last is not a gill, but the homologue of the appendix of 
the pneumostome of Physa and Planorbis ; the animal respires air dis- 
solved in water, but respiration is not active, and the creature can without 
harm remain for a pretty long time in a medium deprived of oxygen. 
Circulation is almost entirely lacunar, as there is a total absence of veins. 
The central nervous system is composed of eight ganglia in A. fluviatilis , 
and of seven in A. lacustris. 
* SB. Ak. Berlin, 1893, pp. 959-62. 
f Rev. Suiss. Zool., i. (1893) pp. 427-61 (1 pi.). 
