(with tin- oxi't'ption of ono ahmirnuil spccimon) all spi'ciniciis at Sta^r I. \V(>rc of the clonj^Mto 

 tvpo; at Stajn' U. tliov aiv novt>r so cloiij^ate as at Sla;,'i' I., altiu)u;,'li both exhibit a rcrtaiii 

 amount of iiulividual variation." 



The iolliiwinL; in h imiat inti i> luuiul in tlir work mentioned: 



Shell: .,Stagi> i"": The male shell is ot about (he type icpiddueed 1)\' me in liy. I 

 abovi'. but not quito so olongatod (It'iifitli : lieijiht abont l.!» : f). Tiic leiualt' shell is somewhat 

 more elongated than the one given by nie in tig. ',i above (..length may be more than twiee the 

 height"). ..'Stage 11": The male shell is rather short and liigli, of about the type reprodueed 

 by (i. W. MClleh, 1906 a, pi. XVIL fig. 23. i.ength : height = about 1.7 : 1. The female 

 shell is still higher; length : height ^ about 1.4 — l,;! : 1. 



First antenna: ..Stage I": The e-bristle in the male is furnished with fiom ten 

 to twelve pairs of spines of the same type and position as has been described by me above. 

 ..Stage IT': This bristle is armed with eight or nine .similar pairs of spines. 



Second antenna: ,, Stage I": The male endopodite is characterized by cla.sping 

 organs^ similar to those reproduced by me above (figs. 7 and 8). The c- and d-bristles (,, basal 

 bristles", according to G. H. FowLEU's terminology) are developed. , .Stage 11": The clasping 

 organ on the right nial(> endopodite has a marked proximal bend (fig. 209); ..with no basal 

 bristles". 



,,R o d - s h a p e d organ: J: ..Stage 1": Of the type reproduced by me above, fig. 4. 

 ..Stage 11": ..The general type is that of Stage 1, but shorter and plumper". $: In both ,, Stage 1" 

 and ,, Stage 11" rather variable; the same types as G. W. MUller observed were found. 



Do ,, Stage I" and ..Stage 11" really represent two succeeding stages of one and the same 

 species? 1 believe that this question must be answered in the negative. The fact which in my 

 opinion forms the strongest argument against this theory of G. H. Fowler's is that in my 

 Antarctic material the oldest larvae were of about the same elongated type as the mature speci- 

 mens. For further information on this point see p. 567 above. 



How are we to look upon ,, Stage 11"? As is shown by the quotation given above the 

 variation in shell-shape was not continuous in the material investigated by G. H. Fowler; two 

 centres of variation could be distinguished. This indicates, of course, that the material was 

 not pure from a systematic point of view. It does not seem to me improbable that ,, Stage 11" 

 belongs to a species very closely related to C. rotundata that has already been described by 

 G. W. MCli.er, 1906 a; this species is C. nasotuberculata. The reasons for this view are as follows: 

 The shell of C. nasotuberculata has about the same shape as ,, Stage 11"; the length also agrees 

 fairly well; cf. G. H. FowLER, p. 273. The clasping organ of the endopodite on the right second 

 antenna in the male is in this species of a type closely resembling that which is characteristic 

 of „Stage 11"; cf. G. W. MCller's fig. 30, pi. XVIII, 1906 a with G. H. Fowler's fig. 209; 

 in both are found what G. W. MULLER describes as: ,,mit auBen wenig abgerundeter rechtwink- 

 liger Ecke". In addition we must note the great resemblance between the rod-shaped organ 

 in pi. 6, fig. 18, G. W. Muller, 1894 and G. H. FowLER's fig. 208. This figure in G. W. MtlLLER 

 is reproduced from a specimen of the same short type of shell and with a similarly shaped clasping 

 organ on the male right second antenna as in ,, Stage 11". In the work just mentioned it was 



