276 DE. G. H. FOWLER— BISOATAN PLANKTON : 



CONCHCECIA SPINIROSTRIS, ClaUS. 

 = C. purrecta, Claus. 



The table of measurements given below seems to show two male and two female 

 stages. Both of the male stages exhibited secondary sexual characters, the longer 

 having more teeth on the armature than the shorter; they may safely be placed as 

 Stages I. and II. But according to the rule which seems to hold good in almost all the 

 grouj)s of ConchoBcia (the ciirta-grou]) excepted, where the males are said to be of the 

 same length as, or even a little longer than, the females), the females at Stages I. and II. 

 are longer tlian the corresponding males ; the presumption therefore is that the females 

 belong to Stages II. and III. 



Dr. Miiller gives poi'recta Claus as a synonym for spinirostvis ("ich lialte C. porrecta 

 Claus, nur fiir gestreckte Individuen von C. spliurostris"). With this I agree, with the 

 slight correction that I hold porrecta as the Stage I. of which spuilrostris is the Stage II. 

 Of the two names the latter has priority. 



As regards the lengths, Claus gives 1'6 mm. without specifying the sex ; Miiller 

 records 1'1-1'6 for females *, 0"95-l'4! for males. The range between these two extremes 

 is rather large for so small a species, and he probably had both stages before him. 



The lengths rej)resented were : — 



Table P. — Total specimens measured: 13 ? +10cJ = ^3. 



As regards the relation witli porrecta — in the females 0"75xl'16=:l-09 ; l-09xl"46 

 = 1-59, which is just within the range observed by Miiller ; the two males at 1'3 are 

 also within his limits. 



Miiller has described and figured (Naples Monograph, p. 183, pi. xxxiv. figs. 1, 2, 3, 5) 

 four young stages of this species, of which the two older at least were males ; all are 

 younger than the ' Research ' specimens. Measured without the rostrum, they Avere 0-33, 

 OM, 0-59, 0-79 mm. Now 0-33xl-35 = 0-44; 0Mxl-35=0-589 (059); 0-589xl-35 = 

 0-79 ; these are therefore related as in other species. As already pointed out (pp. 227-8), 

 it is not likely that the rates of growth will be exactly identical in different sea-climates, 

 but my male means (on only ten specimens) yield a growth-factor of 1-39, which is not 

 very far off the other ; the two sets of observations ouly just fail to fit together, the 



* Piguro measured without rostrum, I'o mm. 



