200 
The hish Nahirahsl. August-September, 
not, however, arrange themselves in hnes. The number 
of rows of teeth in the radula of this species appears to 
vary but Httle with age. Taking the maximum number 
of half rows as the standard, for the number of such rows 
is not always equal on either side of the radula, 13 out of 14 
Dublin specimens dissected were found to have 10, only 
one had 11. These specimens ranged from 6 mm. to 25 
mm. in length. The smaller individuals had usually but 
3 lateral plates with a rudiment of a fourth, the largest 
had 5. , Bergh found the rows of teeth in 4 specimens to 
vary from 14 to 15 ; Meyer and Mobius found the usual 
number to be 12 or 13 ; and Alder and Hancock give 15. 
P. Lessonii (d'Orbigny). 
Frequent in dredgings, both the type and the variety 
ocellata. " Mr. Alder dredged 2 or 3 specimens of this 
species in Dublin Bay, August, 1843, along with P.ocellata^^: 
Thompson '44. Three specimens taken in 10 f. off Bullock 
and one in 8 f. off south side of Howth Head : Colgan '08. 
Dredged ten times in Dalkey Sound in from 7 to 14 f., 1906- 
13, a total of 17 specimens, N.C. The largest of my Dublin 
specimens was 29 mm. long. 
Var. ocellata, Aid. and Hanc. — "Mr. Alder, by means of 
the dredge, took this species commonly and of all sizes in 
Dublin Bay in August last, and subsequently obtained a 
specimen at Malahide " : Thompson, '44. Six specimens, 
taken in 9 f. off Bullock : Colgan '09. Dredged nine times 
off the Muglins and in Dalkey Sound in from 9 to 15 f. 
1906-13, a total of 25 specimens : N.C. The largest 
specimen of this variety, one 14 mm. in length, laid in 
captivity in Sep ember, 191 1, a spawn mass of 3^ coils 
which was cream -white, not pink as is said by Alder and 
Hancock to be usually the case. 
In 6 specimens of the type examined, the number of rows 
in the radula varied from 13 to 14, and the laterals from 
5 to 7 in each half -row. The lateral plates are distinctly 
toothed at the tips as is well shewn by Meyer and Mobius 
in their plate iv. for Ihe var. ocellata. These authors 
