80 



Part III. — Eighteenth Annual Report 



moreover, one which is capable of wide application, since these crabs are 

 common in the creels. 



Wilson* has given some attention to the question of the size of the 

 crab at maturity. He says that it had been repeatedly stated that 

 the berried crabs that are got in the creaves (creels) are larger than 6 

 inches. The smallest berried female of which he had heard was one 

 which Mr. Buglass, fishery officer, said measured about 4 J inches, while 

 the shell of another, 5 T 7 g inches, was shown him by Mr. Story, fishery 

 officer. The smallest crab which he observed with a ripening ovary was 

 inches across the back; none other was less than 5| inches. He 

 sums up his conclusions as follows : — " After carefully examining many 

 hundred crabs at all seasons, I am now convinced that the ordinary 

 size of maturity of the female crabs of the Northumberland coast is 

 above 6 inches. ... A very small percentage are mature when 

 under 6 inches ; a considerable minority mature when between 6 and 

 6-i inches; and between 6 \ and 7 inches the great majority are 

 mature." Couch, in his " Cornish Fauna,"t says that the female crab 

 begins to breed when the carapace is about 3 inches across. In his 

 evidence, given before the Crab and Lobster Commission (p. 55), Mr. 

 Roach, Plymouth, stated that he had once caught a berried crab 4 

 inches across, but that they are generally much larger. 



The evidence which I have collected at Dunbar from the examination 

 of berried crabs, and those having the empty egg-capsules still adhering 

 to their swimmerets,* is given in the following Table ; it does not bear 

 out the conclusions arrived at by Wilson : — 



Sizes of MATURE CRABS (Berried Crabs and Crabs with Empty Egg-capsules). 



Size. 

 Ins. 



Berried 

 Crabs. 



Crabs 

 with 



Empty 

 Egg- 



capsules 



Total. 



Size. 

 Ins. 



Berried 

 Crabs. 



Crabs 

 with 

 Empty 

 Egg- 

 capsules 



Total. 



Size. 

 Ins. 



Berried 

 Crabs. 



Crabs 

 with 

 Empty 

 Egg- 

 capsules 



Total. 



Size. 

 Ins. 



Berried 

 Crabs. 



Crabs 

 with 

 Empty 

 Egg- 

 capsules 



Total. 



4* 





1 



1 



Bf 



4 



3 



7 



6§ 



1 







n 









5 









53 



5 



2 



7 



6£ 



4 



2 



6 



7i 









54 





1 



1 



51 



1 



2 



3 



6| 



1 



2 



3 



7f 









&k 





3 



3 



6 



3 



1 



4 



6f 



3 



3 



6 



n 





2 



2 



Bf 



2 



2 



4 







1 



1 



61 



2 





2 



n 



1 





1 



5J 



1 



1 



2 



« 



3 



3 



6 



7 



1 



1 



2 



71 









BERRIED CRABS, 32; Crabs with EMPTY EGG-CAPSULES, 33. Total, 65. 



The smallest mature crab is one at 4|- inches. Of a total of 65 indi- 

 viduals, 28 were less than 6 inches across ; 37 were over that size. The 

 crabs here recorded were not selected with a view of determining the 

 size of the smallest mature crab, and from evidence supplied by the 

 presence of sperms in the spermatheca T have no doubt that a careful 

 examination of small crabs would reveal a considerable number of 

 mature individuals of less breadth than 5 inches. The crab is mature, 

 however, at a much earlier stage than Wilson supposed. The figures 

 are not sufficient to admit of any calculation of the proportions of 



* Northumberland Sea-Fisheries Committee. Further Report on the Crab Fishery of 

 Northumberland, Newcastle-on-Tyne, 1895, p. 6. 

 + Cf., 2nd edit., 1878, p. 63. 

 t Marked Eh. in Table II., p. 94. 



