186 
Scientific Intelligence . — Zoology. 
ter excited by a clinking sound proceeding from the vessel. On 
separating these naked gasteropods into different vessels, I ob- 
served that the sounds were produced by % the Tritonia arbor es- 
centes , and by them only. The sounds they produce, when in 
a glass vessel, resemble very much the clink of a steel-wire on 
the side of the jar, one stroke only being given at a time, and 
repeated at intervals of a minute or two ; when placed in a large 
basin of water the sound is much obscured, and is like that of 
a watch, one stroke being repeated as before at intervals. The 
sound is longest and oftenest repeated when the Tritonia are 
lively and moving about, and is not heard when they are cold and 
without any motion ; in the dark I have not observed any light 
emitted at the time of the stroke ; no globule of air escapes to the 
surface of the water, nor is any ripple produced on the surface 
at the instant of the stroke ; the sound, when in a glass-vessel, is 
mellow and distinct. I have kept these Tritonia alive on my 
writing table for a month, by renewing their water every other 
day, and giving them occasionally fresh branches of the Sertalaria 
dichotoma, which they are very fond of creeping upon, and from 
which they seem to derive nourishment, by constantly squeezing 
its tender ramifications between their two teeth ; and during the 
whole period of their confinement, they have continued to pro- 
duce the sounds, with very little diminution of their original in- 
tensity. In a still apartment they are audible at the distance of 
twelve feet ; they have been heard by several friends, and by the 
President and a few of the members of the Wernerian Society. 
The sounds obviously proceed from the mouth of the animal ; 
and at the instant of the stroke we observe the lips suddenly se- 
parate, as if to allow the water to rush into a small vacuum form- 
ed within. As these animals are hermaphrodites, requiring mu- 
tual impregnation, the sounds may possibly be a means of com- 
munication between them ; or if they be of an electric nature, 
they may be a means of defending from foreign enemies, one of 
the most delicate, defenceless, and beautiful gasterophods that 
inhabit the deep. — Dr Grant. 
88. Pecten niveus, a new species.— -It having been suggest- 
ed, in hasty terms, in the number of the Annals of Philosophy 
for November last, that the Pecten niveus , described in vol. xiii. 
p. 166. of the Philosophical Journal, is perhaps a mere variety 
