192 
The Irish Naiiiralist. August-Sf^ptcmbcr, 
Specimens was intermediate in colour between L. flavidiis 
and L. 7narmoratus. The publication by Sir Charles 
Eliot (Part viii., Monograph) of Hancock's figure of L. 
■portlandicus convinces me that I was not justified in regard- 
ing the caudal extension of the pallial margin there shown 
as a sufficient specific character. This species is accord- 
ingly merged here with the other Britannic species of 
the genus under the name L. mannoratus which has 
priority. 
As shewing the wide range of variability in the radula 
due merely to age, it may be of interest to note here that 
an individual 2-5 mm. in length (one of the seven juveniles 
taken at Skerries in 1912), yielded on examination the 
dental formal 20 x 6-0-6, as contrasted with the formula 
40 X 58-0-58 given by one of Mr. Farran's Irish Sea 
specimens 33 mm. long. In the juvenile Skerries speci- 
men, the number of teeth in the first of the 20 rows was 
but 2 on either side of the centre, increasing to a maximum 
of 6 on either side in the 20th row. The larger teeth 
bore on either side from 10 to 12 denticles against 25 found 
by Eliot in the teeth of a mature Plymouth specimen. 
The jaw tesselations in the juvenile Skerries specimen were 
perfectly formed, the outer slightly curved edge of each 
tessellation being minutely and regularly dentate or rather 
crenate. 
On the whole, the evidence at present available would 
appear to warrant the conclusion that we have in Britannic 
waters but one highly variable species of Lomanotus 
which presents itself in two leading forms or colour varieties. 
If L. fiavidm should prove to be a mature form, and not, 
as iliere is good reason to believe, a juvenile, then it may 
be entitled to rank as a distinct species. 
Doto coronata (Gmelin). 
Locally abundant in shallow water dredgings and between 
tide marks ; occasional in deeper water. Found in Dublin 
Bay by Mr. Alder ; Tho7npscn, '44. In 2f. in Malahide 
River, June, 1908, 33 specimens on Hydrallmania ; Colgafi, 
'09. Taken in 30 dredgings in from 2 to 15 f. at Skerries, 
