448 Miscellaneous. 
zoéa from the eggs, was interested to find that the larva was of a 
form much more advanced than in the zoéa of other Anomura 
described and figured by Fritz Miullerin his suggestive work entitled 
“Facts for Darwin.” Indeed the metamorphosis appears to be 
abbreviated ; and the larva, on hatching, closely approximates the 
form of the adult, as in the case of the development of the lobster, 
the crayfish, and of Palemon adspersus and Eriphia spinifrons (the 
three latter observed by Rathke). The eyes were developed on very 
short peduncles, being almost sessile. The embryo was near the 
time of hatching, though the yolk was not entirely absorbed. 
The two pairs of antenne were well developed and hung down 
behind the large claws ; the five pairs of legs were well developed, 
the joints distinct, and the first pair were about twice as thick as 
the others, the claws rather large, but not so disproportionately so 
as in the adult form, but as much so as in the larva in the second 
stage of the lobster, figured by Prof. Smith. The eyes were large, 
but nearly sessile. The abdomen was broad and flat, spatulate at 
the end much as in the adult; there were five pairs of abdominal 
teet or swimmerets, each with an endopodite and exopodite, like those 
seen in the second larval stage of the lobster. 
It thus appears that Alpheus heterochelis hatches in a stage more 
advanced than the first larval stage of the lobster. Unfortunately 
the specimens, though carefully preserved for several years, finally got 
misplaced ; so that it is not possible for us to give a more detailed 
description of the young at the time of birth.—Amer. Nat., Oct. 
1881. 
Observations on the Rotifera of the Genus Melicerta. By M. Joxrer. 
The observations here summarized. were made upon two species 
of Melicerta, namely Melicerta ringens and an allied species distin- 
guished by the presence of a long thread that fixes it in its sheath. 
With the exception of a few details, all that applies to the one 
apples to the other. 
Nervous System.—Several authors, following Huxley, have stated 
that the ganglion of the Melicertina is situated near the mouth, and 
consequently ‘at the surface of the body opposite to the anus. This 
would be the reverse of what exists in all Rotatoria. In reality, 
what these observers have taken for the ganglion is a gland, both in 
its structure and in its situation and functions. The true nervous 
centre is on the opposite side, on the dorsal surface of the pharynx. 
It consists of a group of large cells of very characteristic form, and 
furnished with a voluminous nucleus. Several similar cells are ar- 
ranged by the side of the former, and extend in different directions. 
This centre a good deal resembles that described by Leydig in the 
genus Lacinularia. It is not voluminous ; and I think that the 
comparatively enormous ganglia that have been described in several 
Rotatoria are glands, and that the true nervous centre is still to be 
sought. 
In any case, we see that the anomaly created for the Melicertina 
