400 Dr. J. A. Grieg on the Age of some 
XXXIX.—Remarks on the Age of some Aretic and North- 
Atlantic Starfishes. By James A. GrieG, Curator of the 
Bergen Museum, Bergen, Norway. 
Dr. MorTENSEN has shown, in  Smaa faunistiske og biolo- 
giske Meddelelser” *, that ophiurids of various ages are found 
simultaneously in shallow water at the same locality within 
the boreal region ; transformed young were collected recently, 
together with one-year old, fully developed two-year old, and 
older individuals. At Sallingsund Dr. Mortensen obtained 
young of Ophiura ciliaris with a disc-diameter of }-} mm., 
one-year old individuals with a disc-diameter of 3-4 mm., 
two-year old ones with a disc-diameter of 7-11 mm., and 
several whose disc-diameter was more than 12 mm. and 
whose age was probably three years. 
The circumstances are the same on the Norwegian southern 
and western coasts; on the other hand, Dr. Mortensen in 
“ Kehinoderms from Hast Greenland ” T mentions that a large 
number of Ophiura sarsi obtained off Jan Mayen were all of 
about the same size (disc-diameter 15-20 mm.). As nume- 
rous specimens of Ophiura robusta, a very small species, 
were taken in the same haul, the small Ophiura sarst could 
not have been overlooked. At Jan Mayen there could only 
have lived a single year-class of Ophiura sarsi, whose age 
Dr. Mortensen estimates at one year, though I am most 
inclined to estimate it at three years. 
An examination of the ophiurids collected by the ‘ Michael 
Sars’ in the Norwegian Sea shows that very often a single 
year-class occurs at a locality, exactly as stated by Dr. Mor- 
tensen in regard to Jan Mayen ; but several year-classes may 
also be found—in this case, one of them is generally more 
numerously represented than the others {. 
In this paper I shall confine my remarks to a haul which 
the ‘Michael Sars’ made in the summer of 1914 off the 
mouth of the Varanger Fjord. From this haul 157 Ophiura 
sarst were obtained with a disc-diameter of 16-27 mm., and 
one specimen measuring 11 mm.; of these.no fewer than 99 
(or 63 per cent.) have a disc-diameter of 22-24 mm.—this 
large group represents a year-class whose age must be put at 
four years. There were also several individuals—not very 
* Vidensk. Meddel. 1897, p. 321. 
+ Meddel. om Grénland, xxix. 1903, p. 82. 
t ‘Bergens Museums Aarbok,’ 1903, no. 18, p. 23. 
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