382 



Part III. — Twentietli Annual Beport 



Y. The Firth of Clyde. 



A number of hauls were made in the Firth of Clyde between the 

 island of Pladda and Turn berry Point in August, September, October, 

 and December 1899, the shrimp-trawl of the " Garland " being used. 

 The depth varied from about thirty to over foi-ty fathoms. The 

 measurements contrast with those obtained on the East Coast, and 

 show that the long rough dab grows more slowly in the Clyde (PI. XIX.). 



The first series was represented in a haul on 30th August by four 

 specimens, from 41 to 45 mm. in length, and having an average size of 

 43"5 mm. On 14th September ninety-one belonging to this series had 

 an average length of 45*0 mm.; of these, forty-one were females ranging 

 from 39 to 52 mm., the mean size being 45*8 mm., twenty-three were 

 males from 41 to 50 mm., and having an average length of 45'6 mm. 

 On 1 2th October the mean size of 232 specimens had increased to 48*9 mm., 

 the range being from 40 to 57 mm. In December (15th to 18th) the 

 mean length of twenty - nine specimens was 52"6 mm., the range 

 extending from 46 to 59 mm. On 3rd April 1900, ninety-five specimens, 

 varyingfrom49 to 64 mm., had an average size of 55*5 mm., or 2^^^ inches, 

 the females, fifty-seven in number, averaging 55*8 mm, and the males, 

 numbering thirty-eight, averaging 55*1 mm. 



Thus the increments of growth of this series in the intervals between 

 the various hauls were as follows: — 



The increase of 12 mm. (scarcely half an inch) in the period indicated 

 is very small, and conti-asts with the more rapid growth on the East 

 Coast, as shown by the following particulars referring to the northern 

 part of the North Sea, oft' the Shetland Isles (I.), and the deep water off" 

 Aberdeen (II.). 



[Table. 



