378 G. B. GRASSI. 
well-known lateral branch of the fifth pair of the cranial 
nerves exists. It is also found in Leptocephalus brevi- 
rostris. This lateral branch could not be found by Dr. 
Calandruccio in the other common Murenoids of Sicily, and 
is wanting also in the other Leptocephali. 
The mucous-canal-system (sensory canals) in the head are 
already developed, partially in Leptocephalus_ brevi- 
rostris, and are incompletely developed in the elver. As in 
the elver, so in Leptocephalus brevirostris, the pyloric 
ceca are wanting. ‘The blind extremity of the stomach and 
the incompletely developed swim-bladder, which is as yet free 
from contained gas, are present both in Leptocephalus 
brevirostris and in the elver of Anguilla vulgaris. The 
pronephros is in active function, as in the other Leptocephali. 
The Malpighian glomerules of the kidney (mesonephros) are 
lobed as in the eel, and their number corresponds with that 
observed in the Helmichthys stage, of which I will speak 
further on. The genital gland, not yet sexually differentiated, 
is almost identical with that of the same stage. In short, it 
may be said that the whole organisation of Leptocephalus 
brevirostris corresponds with the organisation of the common 
eel, if we make allowance for those changes which are 
observed in the metamorphosis of the other species of Mure- 
noids, such as reduction of the pancreas and of the liver, dis- 
appearance of the protoskeleton, complication of the muscu- 
lature, increase in size of the cerebellum, loss of the larval 
teeth, development of the definitive teeth, &c. 
From the description of these Leptocephali I must pass on 
briefly to speak of the stages nearer to the condition of the 
elver. I am, however, obliged to leave a break in the series, 
which, however little its significance, yet certainly will make 
some impression on the minds of those who do not realise with 
what caution I have formed my conclusions. I must confess 
that since I have learnt how difficult it is to procure an entire 
series of the development of a Murznoid, I am more astonished 
at being able to recognise a single stage in the development of 
a given species than at not finding the whole series. I must 
