ON THE FAUNA OF IRELAND. 245 
Report on the Fauna of Ireland: Div. Ynvertebrata. Drawn up, at the 
request of the British Association, by Witu1AM TuHompson, Esq., 
President of the Natural History and Philosophical Society of Bel- 
Sast. 
Introduction. 
In the former portion of my Report on the Fauna of Ireland, laid before the 
meeting of the British Association at Glasgow in 1840, the Vertebrata only 
were included*. In the continuation now presented, are all the native species 
of Invertebrata—Mollusca, Crustacea, Cirrhipeda, Annelida, Foraminifera, 
Entozoa, Echinodermata, Acalepha, Zoophyta, Amorphozoa—excepting In- 
secta and Infusoria, using the former term in its widest sense. 
For the whole of the information in some departments I am indebted to 
others: of a portion undertaken by myself, I have only yet obtained a super- 
ficial knowledge. A want of unity will be observable throughout in the treat- 
ment of the various subjects, the most obvious point of which to some natu- 
ralists will be in the nomenclature :—the first names bestowed on the species, 
which according to the just rule of priority (see British Association Rules 
of Nomenclature) should be those used, could only be partially ascertained 
within the allotted time. 
This Report does not embrace so comprehensive a view as I originally con- 
templated with respect to widely-extended comparisons, and the causes which 
seem to operate on the distribution of the various classes, &c. of Inverte- 
brata, but as now given, it may afford data to others better qualified to do 
justice to that subject. It wili in its present state only have a value in record- 
ing the species indigenous to Ireland, and offering a comparison between them 
and those of Great Britain, but this is not unimportant with regard even to 
the general geographical distribution of species. The European Fauna, it 
need scarcely be observed, could not be perfected without that of Ireland 
being known, which latter is again especially interesting, in consequence of 
our island being within its latitude the extreme western limit to which all the 
species included in it range that are peculiar to the eastern, or in other words, 
are not found in the western hemisphere. 
The Fauna of Ireland, compared with that of Great Britain, exhibits the 
falling off of species westerly compared with that island, which again on its 
part (though not treated of here) presents a similar falling off westerly com- 
pared with tlie opposite shore of the continent. An example may be neces- 
sary in explanation, and the most striking will be selected, though the subject- 
matter belong to the former part of this Report. Thus, of the class Reptilia 
_ there are in 
Beterumt. Great Brirain. IRELAND. 
Order Sauria. 
Lacerta ...... 3 species... 2 species (same as Belg.)... 1 species (same as Brit.). 
Anguis......++. 1 pate peaetanatite fh oy Pe a Our ss 
* The species of Vertebrata since added to our catalogue are— 
Turdus Whitei, Eyton, Ann. Nat. Hist. vol. xi. p. 78. 
Pycnonotus chrysorrheus, Swains. See present volume. 
Cuculus glandarius, Lin., Ann. Nat. Hist. vol. xii. p. 149, and present volume. 
Glareola pratincola, Lin. (sp.) See present volume. 
Naucrates ductor, Cuv. and Val, See present volume. 
The Lepus Hibernicus and L. variabilis are now proved to be of the same species 
(see present volume): respecting the animal provisionally called Mus Hibernicus no 
further information has been obtained. 
+ According to the excellent ‘ Faune Belge’ of De Selys-Longchamps. 
