i6 



Heter ocalanus medius Wolfenden, may be the species described by Kroyer 1848 — 49 

 as Calanus cristattis. Two figures of the forehead of Kroyer's species are given by Giesbrecht 

 in 'Fauna und Flora des Golfes von Neapel' (pi. 6, figs. 14 — 15). 



Genus Undinula nom. nov. 

 = Undina Dana, 1847. A name preoccupied by Gould, (Aves) 1836 and Munst., (Pisces) 1842. 



Giesbrecht 1893, combined the genus Undina Dana, with Calanus Leach, and with 

 the exception of Sars, subsequent workers adopted this plan. Sars 1902, p. S, points out that 

 the structure of the fifth feet of the male of Undina differs considerably from the males of true 

 Calanus, and that the genera ought properly to be kept apart. Very little examination of the 

 fifth feet of the males of the types of the two genera is required to shew that Sars view is 

 the correct one. There is no similarity between the left fifth foot of the male of Calanus 

 finmarchicus, and that of the male of Undina vulgaris. The males of Dana's Undina have 

 the last joint of the exopodite of the left fifth foot developed into a well defined prehensile organ. 



The generic name used by Dana had been established for a genus of birds previous 

 to its adoption by that author and Undinula has, therefore, been substituted for Undina in 

 the present report. 



The females of Undinula differ very little in the structure of the appendages from typical 

 Calanus, the only noticeable distinction is an incomplete division of the eighth and ninth joints 

 of the antennules. There are five pairs of bi-ramose feet, all adapted for swimming, and each 

 branch is three-jointed. The males are very easily recognised by the structure of the fifth pair 

 of feet. The foot of the right side is bi-ramose and each branch is three-jointed. The left foot 

 has the exopodite considerably elongated and its last joint is converted into a powerful bi-ramose 

 prehensile organ. The endopodite of the left foot may be entirely absent as in Undinula 

 vulgaris, or very rudimentary, consisting of one small joint, as in Undinula darwini and Undinula 

 caroli. There are at present three species belonging to this genus and they were all noted in 

 the 'Sibogra' material. 



&■ 



1. Undinula vulgaris (Dana). 



Undina vulgaris Dana, 1849, PP- I 7> 1 ^> 22 - 



Undina vulgaris Brady, 1883, p. 53, pis. XV & XVIII. 



Calanus vulgaris Giesbrecht, 1893, p. 92, pis. 6, 7, 8. 



Undina vulgaris T. Scott, 1893, p. 44. 



Calanus vulgaris Giesbrecht, 1895, p. 248. 



Calanus vulgaris Giesbrecht & Schmeil, 1898, p. 17. 



Calanus vulgaris I. C. Thompson, 1900, p. 275. 



Calanus vulgaris Cleve, 1901, p. 5. 



Calanus vulgaris A. Scott, 1902, p. 400. 



Calanus vulgaris Thompson & Scott, 1903, p. 242. 



Calanus vulgaris Cleve, 1903, p. 357. 



Calanus vulgaris Cleve, 1904, p. 186. 



Calanus vulgaris Wolfenden, 1905 (a), p. 994, pis. XCVT & XCVII. 



Undina vulgaris Sars, 1905 (a), p. 2. 



16 



