174 
The irtsk Naturalist. August-September, 
specimens, and 21 in the other, while the smaller specimen 
had 20 teeth in its radula with fully 20 discarded worn 
teeth in the ascus. 
In Dublin this species varies much in colour. Bright 
green specimens are much less frequent than those of dull 
olive or reddish brown tints. As Pelseneer has shown for 
the variety or form aurantiaca, these colours are derived 
from the food plant. Emerald green individuals placed 
by him on red sea -weeds were found to have changed colour 
from gveen to the red-brown of aurantiaca in the space of 
18 days. On the Dublin coast the typical green form was 
found to feed on the green sea-weed, Cladophora rupestris. 
Limapontia capitata (Miiller). 
L. nigra. 
Locally abundant in stagnant pools between high-water 
and half-tide marks, almost invariably on Cladophora 
rupestris ; occasional in shallow water dredgings. In half- 
tide pools at Bullock, where 47 specimens were taken in 
three gatherings, May-June, 1908 ; one specimen dredged in 
2 f., Malahide River, May, 1908 ; several specimens at 
Red Island, Skerries, and 2 on Shennicks Island, July, 
1908 : Colgan, '09. Nine specimens at Dalkey Island, 
June, 1908 ; 107 at Bullock in 8 gatherings, 1909-13, from 
I to 52 in a gathering ; 9 at Rush in 1910, and 7 at Skerries, 
July-August, 1910-12 : N.C. Largest, 5 mm. long in 
motion. 
This species spawns very freely in captivity, the egg- 
masses being elongate, pear-shaped, slightly curved, and 
from 2 to 6 mm. in length. They contain numerous (from 
50 to 100) small globular eggs with a yellow yolk suspended 
in clear lluid. A single pairing is sufficient for the fertiliza- 
tion of several egg -masses. A specimen from Bullock 
isolated on the 19th June, 191 2, laid no less than 10 distinct 
egg-clusters between that date and the 30th of the same 
month. Although in many cases development proceeded 
up to the stage of rapid revolution of the embryo within 
the egg, in no instance did the veliger succeed in breaking 
free from the shell. Some of the specimens were found to 
be infested with parasites, apparently copepod crustaceans 
