Sliiilics ON marine O.sIt'.k oils • 055 



S h (■ 1 1: Jifiigth. 1,15 JUiii. iSccii iioiu the side it is rather eiungated; pi. XXN'lIl, 

 fig. 42, the shell of a female, seen from the side, shows, as has been pointed out above, a type 

 that agrees fairly closely witli the one luund by me in the Antarctic. 



First .-intenna: The e-l)ristle in the male is furnished witli ten pairs of s[)ines 

 of about the same type and position as has been shown by me above. 



R o d - s h a p e d org a n: The capitulum varies in type; in the male it is sometimes 

 of the type reproduced by me in tig. 4 above, sometimes almost straight and distally rounded; in the 

 female types were found that resembled rather closely those found by me in the Antarctic specimens. 



No difference is mentioned between the male and female shell nor any variation in the 

 shape of the shell, nor is any variation mentioned in the armature of the e-bristle on the male 

 first antenna. 



a. \V. MCLLEU's description of this species, 1906 a, is based on sjjecimens from the 

 Atlantic, Antarctic and Indian Oceans. The following information is given in this description: 



(Shell: ,,Von sehr wechselnder Form, das Verhaltnis zwischen Hohe und Liinge 

 schwankt zwischen V, and Vm" (i. e. about 1 : 1,75 to 1 : 2,37). In short specimens the posterior 

 part of the shell ck)minated rather strongly over the anterior part, in the most elongated ones 

 the anterior part of the shell was about as large as the posterior })art. The posterior margin 

 of the shell was more or less strongly rounded; as a rule the elongated specimens were characterized 

 by a very decided arcuation, the shorter ones, on the other hand, had a somewhat weaker one. 



First antenna: With regard to the e-bristle it is remarked in the text that it 

 agrees with this bristle in C. nasotuberculata; in the latter species this bristle is said to be armed 

 with ,,etwa" twelve pairs of spines; in ])l. XVII, fig. 34 eleven spines are drawn on this bristle. 



Second a n t e n n a: To judge from the figures the c- and d-bristles are developed 

 on the endopodite in the male. For the clasping organs see p. 651 above. 



Rod -shaped organ: In the male the capitulum is of about the type reproduced 

 by me in fig. 4 above; in the female this appendage varied within about the same limits as in the 

 Antarctic specimens investigated by nie; cf. p. 654 above. 



No information is to be found in this treatise as to whether the variation of the shell 

 was continual or whether specimens with different types of shell were found together at the 

 same localities. The statement quoted on p. 649 above as to the length of the shell perhaps indicates 

 that the Antarctic specimens investigated by this author were also all characterized by having 

 elongated shells. 



G. H. Fowler, 1909, looks upon the elongated forms as ,, Stage I", the short ones as 

 ,, Stage 11" ; cf. p. 567 above. With regard to this question this author writes as follows : ,, According 

 to Dr. Mi'LLEH, the shells of this species exhibited a remarkable variation in shape, the height 

 being anything from 41 to 57 percent, of the length. Now in aU other Halocypridae which I have 

 handled the shell-shape is very fairly constant, and the general contour gives one of the most 

 rebable specific characters, but its diagnostic value would be seriously weakened if so great 

 a range of variation were possible as is shown in MtiLLEli's figures, pi. XVII. 23, 24 and 25, 26. 

 Fortunately, it appears that this extreme range of possible contour is due, not to individual 

 variation, but to the different shapes of the shells at Stages I. and II. So far as I have seen 



