266 



UK. G. H. FOWLEE — BI8CATAN PLANKTON : 



The ratios for Brooks's law come out sufficiently clearly, although the total numbers 

 are small, and in spite of the difficulty of separating this species from magna * at the 

 lower stages. 



Taking the means as a basis for calculation : 



2 1-07 X 1-48 = 1-58 ; 1-58 X 1-48 = 2-33. 



6 0-77 X 1-40 = r078; 108 X 1-4 = 1-51; 150 X I'i = 210. 



Taking from fig. E the probable extremes of females at Stage II. as 1-3 and 1"8, wc 

 ^ei the probable extremes for Stage I. as 1-9 and 2*6 ; similarly taking the extremes for 

 males as 1-3 and 1"7, we arrive at 1"8 and 2*38 as the probable extremes for Stage I. 



This by itself would throw doubt on Juday's record of 29 for a male ; besides which, 

 he notes only " about twenty pairs " of teeth as the armature of the principal bristle of 

 antenna I. As his brief description is not accompanied by figures, it is not apparent 

 what species was before him, but it was probably not hyalophylluni. 



Fig. E. 

 tiim 



& 



CoNCHCECiA IMBRICATA (Brady pars), Miiller. 

 The actual measurements of this species have been given in the Introdviction (p. 225) 

 and need not be repeated here. As already mentioned, on the analogy of other species, 

 there can be little doubt that an older stage exists than any which has yet been recorded 

 with a probable mean length of about 2 3-65, s 2-76. The measurements given by 

 Miiller for this species seem to have included rostrum and spine. 



* It is quite possible that some hyaloitliyllum at Stage III. have boon placed with viar/na at Stage III. 

 possible that some liyalophyllwH Stage IV. have beeu ranked as '• A " larva) (compare p. Ii45). 



it is 



