33 



experiment was repeated several times, so that there was no 

 doubt about the actual fact. Provided that this was not 

 brought about by the artificial surroundings or condition of 

 the larvae, it would seem to point to the reason why so few 

 phyllosomas were found in townettings as they might have 

 retreated to the darker or more shady parts. 



It is to be noted that the crawfish in the swimming stage 

 did not exhibit any great timidity in its movements but 

 moved about rather slowly and apparently fearlessly. Most 

 small crustaceans dart away rapidly on the approach of 

 suspected danger, but these forms only moved off slowly, on 

 being threatened by any object suddenly brought near them. 



8. Age. Rate of Growth, etc., of Crawfish. 



Very httle is known with regard to this subject. The 

 first free swimming stage, after hatching, lasts only a few 

 hours as has been recorded, but how long the second stage 

 lasts, and how many changes take place before the ground 

 form is assumed is not known. This is of importance with 

 regard to the question of the possibility of artificial rearing 

 of the fish, and indicates a direction for future investigation 

 of economic importance. 



At what size or age the female reproduces is also of im- 

 portance. If one can rely on statements of various observers 

 this occurs at a very small size. Unfortunately these state- 

 ments may be consciously or unconsciously influenced by 

 ulterior considerations, and they have never been confirmed 

 by producing the actual specimen. The smallest female 

 carrying eggs which I have been able to procure was much 

 larger than the sizes stated, and measured 2| inches in length 

 of carapace. 



The size of the largest female is of even greater importance. 

 It is stated that at Hoetjes Bay Factory they have been got 

 up to 51 inches, though very seldom, and always in deep 

 water — perhaps such large specimens are old and past breeding. 

 A female of between 5 and 6 inches has also been got at Hout 

 Bay Factory, but this was considered a giant and very ex- 

 ceptional. As a rule, females do not usually much exceed 

 4 inches in length of carapace. 



Males, on the other hand, grow to a much larger size, and 

 have been seen about 9 inches in length of carapace. That 

 these are probably very old males is indicated by the fact 

 that they are generally covered with various growths, especially 

 hydrozoa, which give them a hairy appearance — hence the 

 idea among fishermen that old males grow hairs. The presence 

 of these growths on the shell probably indicate old age, as, 

 at this time of life the shell is not shed so frequently, if at all. 



[C.P. 5-13] 



