TRANSACTIONS OF THE SECTIONS. vai 
Dr. Allman read a paper ‘ On the genus Cirropteron, Sars.’—In this communication 
it was maintained, that the genus Cirropteron had no real existence, having been 
founded by Sars on the imperfectly developed condition of a gasteropodous mollusc. 
Dr. Allman had himself bred from the ova of a gasteropodous molluse animals refer- 
able to Sars’ genus; and the singular ciliated disks with which the larvz of buccinum, 
trochus, &c. are furnished, have been noticed by other observers. Dr. Allman called 
attention to the remarkable analogy which exists between these molluscan larve and 
the Rotiferze, and advocated the necessity to the zoologist of an accurate knowledge, 
not only of the anatomy of the various organized beings which come under his obser- 
vation, but of their history during the entire period of their existence. 

On a new Genus of Terrestrial Gasteropod. By Dr. ALLMAN. 
This highly interesting animal was found last autumn in the county of Kerry by 
Mr. Andrews of Dublin. Dr. Allman examined it, and convinced himself of its en- 
tire generic distinctness and importance. It constitutes a connecting link between 
Arion and Limax, differing from the former in the possession of a well-developed in- 
ternal shell, and in the position of the genital pore, which is placed, as in Limax, 
behind the root of the right small tentacle; and from the latter, in the orifice to the 
respiratory sac being in the anterior margin of the shield, and in its truncated glandu- 
liferous tail. To the new genus, which it was therefore necessary to constitute for 
the reception of the gasteropod, Dr. Allman gave the name Geomalacus; and to the 
present species, the only one of the genus as yet discovered, the specific name macu- -.. alin, 
losus is appropriated. 
Synopsis of the Genera and Species of Zoophytes inhabiting the fresh waters Beier 
of Ireland. By Dr. ALLMAN. 
The freshwater Zoophytes of Great Britain have hitherto been all included under 
the following four genera, Hydra, Cristatella, Alcyonella, and Plumatella. Of these, 
Hydra is made to include four British species,—Cristatella one, Alcyonella one, and 
Plumatella has been described as containing three species. Of the above nine species, 
the author was of opinion that two must be erased, viz. the Hydra verrucosa of Temple- 
ton, which appears identical with H. fusca, and the Plumatella gelatinosa of Fleming, 
which is evidently the same with Blumenbach’s Zubularia sultana. To the seven 
species which remain, Dr. Allman was enabled to add five, of which four do not ap- 
pear to have been before noticed, and the other is only found described in the Fauna 
of the Continent. The zoophytes at present included under Plumatella were distri- 
buted in the synopsis between two genera, those with crescentic discs being retained 
under Plumatella, while those whose discs are circular were removed to /redericella, 
a genus established by M. Gervais for this form of ascidian zoophyte. An important 
addition now made to the British zoophytes is Paludicella, discovered by W. Thomp- 
son, Esq. at Lough Erne, in the autumn of 1837, and since obtained abundantly by 
Dr. Allman in the Grand Canal near Dublin. In October 1842, a hydroid zoophyte 
of much interest was discovered by Dr. Allman in the Grand Canal, Dublin ; it is re- 
ferable to no known genus, and occupies a position between Coryne and Hermia. 
For the reception of this zoophyte, therefore, he has been obliged to form a new 
genus, to which he has given the name Cordylophora. The synopsis, therefore, em- 
peat several new species and two genera, now for the first time added to the British 
‘auna. 

On the occurrence of Calothrix nivea, and the Infusoria of sulphureous waters 
at Cove, Ireland. By E. Lanxester, M.D., F.L.S., $e. 
_ At previous meetings of the Association the author had given an account of the 
occurrence of the Calothriz nivea, in most of the mineral springs of England and 
Scotland, as well as in other localities where sulphuretted hydrogen was spontane- 
ously formed. He had also found with this plant several species of Infusoria, inhabiting 
sulphuretted hydrogen springs, some of these forming beautiful crimson deposits, at 
the bottom of the springs from which the water flowed. He had recently found the 

