fiO 



TAGR SKOC^.SBERC. 



whether these folds are arranged segmentally or not). Fr. MtJLLER, 1870, p. 273, had already 

 expressed this view; as did C. Claus also, 1876, p. 96. As a proof of the probability of this 

 assumption it may be pointed out that weak transverse folds have been observed on the 

 dorsal side of the back of the body in the males of a number of species belonging to other genera 

 of Cypridinids; cf., for instance, Cypridina dorsoserrata G. W. MtJLLER, 1908, pi. IV, 

 fig. 2. In the male of Cypridina Hilgendorfi G. W. MtJLLER, 1890, we find at the corresponding 

 place gills in the form of comparatively high transverse folds, seven in number; as in the 

 last-mentioned species but contrary to the genus Asterope, these folds extend across the back 

 without any median break; only the foremost one has a medial concavity. G. W. MIJLLER, 

 1890, p. 224, homologizes these gUls with those of the genus Asterope, supporting his view 

 especially by their number and position. It is, at any rate, certainly premature at the present 

 time to describe these gills by the term „epipodial appendages" . 

 Furca. ' F u r c a: — 



With regard to this organ the terminology used by G. W. MtJLLER has been adopted 

 in this work. Consequently the furcal claws are counted distally-proximaUy, contrary to the 

 practice of a number of other writers, e. g. G. S. BRADY. This method is necessitated partly 

 because in several forms these claws vary in number, when it is always the small proximal claws 

 that are subject to variation, and partly because they are formed ontogenetically distally- 

 proximaUy, the proximal ones not appearing until the matm-e stage is reached. 



Frontal organ*: — 



This is most fi-equently termed in the present work ,,the rod-shaped organ", on 

 account of its shape. 



With regard to other organs the terminology used by G. W. MtJLLER has been 

 adopted in this work. 

 The larval stages. Terminology of the larval stages: — • 



By Stage I in the present work is meant the oldest larval stage, the stage next to 

 the mature stage. The stage immediately preceding Stage I is called Stage II, the stage 

 immediately preceding Stage II is Stage III, and so on. 



This terminology has not been used by previous writers. C. Claus and G. W. MtJLLER 

 denote the youngest freely living larval stage by Stage I, the subsequent stage by Stage II, 

 and so on. This terminology seems inconvenient on account of the deficiency of our present 

 knowledge of the post-embryonal development of this group, especially with regard to the 

 youngest larval stages. A consequence of the employment of this terminology has been that 

 larval stages with the same numbers do not correspond to each other in the works of different 

 writers or even in different works of the same writer. Thus Stage I of the genus Condwecia 

 in G, W. MOLLER's works of 1893 and 1894 — of which tliis author says, 1893, p. 376, ,,Das 

 erste mir bekaunt gewordene Stadium, das ich geneigt bin, fiir das erste iiberhaupt zu halten" 

 — corresponds to Stage III of the same genus in C. Claus, 1893. 



Frontal urg 



Other 



* Contrary to the praL-tic'i; in (',. W. AIullku's wmiUs. in Ihis tiralisr. as m W . Giksbki;ciit. I'.li;i. the nauplius 

 L'.Vf is not ix'ckonfd as a frontal oi-gan (W. OiicsnnKciiT, lyi:i. [: 12(i). G. W. Mli.i.kh writes. I<)1-i. p. 8; .,l>as Fronlal- 

 organ . . . bostnhl aus deni dreitciligen Mediaiiaiigc and . . . ." 



