1895.] Zoology. 587 
ZOOLOGY. 
Habits of Limpets.—It has long been known that the common 
limpet (Patella vulgata) settles down on some eligible spot (its “ scar % 
between tide-marks, and makes a home, to which it returns after having 
been out to feed. This locality-sense has been supposed to be independ- 
ent of smell, sight and touch, so far as the head tentacles are concerned. 
Mr. Lloyd Morgan, however, has shown (Nature, Dec. 6, 1894) that 
the head tentacles are the sense-organs concerned with this “ homing” 
power. Later observations made by J. R. A. Davis, at the Scottish 
Marine Section, confirm Mr. Morgan’s conclusions, to some extent, but 
Mr. Davis is inclined to think that the mantle tentacles may help in 
the homing. 
Mr. Davis notes also that this homing faculty is not confined to 
Patella, but is also possessed by Helcion pellucidum. The object of 
this habit seems to be protection from the assaults of the incoming or 
outgoing tide. (Nature, March, 1895). 
Life-History of the Lobster.—With a view to the artificial 
culture of the Lobster, Mr. Samuel Garman has undertaken to study 
the life-history of this animal, and has published the following notes on 
their breeding habits: 
1. The female lobster lays her eggs but once in two years. 
The normal time of deposition is when the water has attained its 
summer temperature, varying with seasons and places ; the period ex- 
tends from about the middle of June to the middle of September. 
3. The eggs do not hatch until the following summer, that is, for a 
ear. The time of hatching varies also with the temperature, and 
extends from the middle of May to the last of August. 
The Gas in the Swim-bladder of Deep-Sea Fishes.— 
During the last scientific voyage of the yacht Princess Alice, com- 
manded by Prince Monaco, M. Jules Richard had an opportunity of 
analyizing the gas in the swim-bladder of several species of deep-sea 
fishes. Serranus, from a depth of 60 meters, and congers, taken from 
a depth of 175 meters oft the bank of the Gorringe, showed more than 
80 per cent. of oxygen. The rest of the gas was nitrogen with traces 
of CO,. The proportion of oxygen was such that it was easy to perform 
the well known experiment of lighting a candle by holding one in the 
