CYAMIDAE 307 



Family CYAMIDAE 



Lutken, 1873, p. 231; 1887, p. 317; 1893, p. 421. 

 Stebbing, 1888, pp. 155, 419 and 1647-1648. 

 Sars, 1895, p. 668. 

 Stebbing, 19100, p. 471. 

 Chevreux, 1913, p. 183. 

 Chevreux and Fage, 1925, p. 461. 



The present collection is small, but important, because it contains the first recorded 

 specimens of Whale-lice from a Balaenoptera. Lutken (1873) notes that no Whale-louse 

 was known from a true Fin-whale {Balaenoptera) ; and the previous statements as to the 

 presence of a species on the Cachalot remained unconfirmed until Pouchet in 1892 

 described C.physeteris (syn. fascicularis, Verrill, 1903). Moreover P. boopis, the common 

 louse on the Humpback, has now been found on a Sperm Whale. 



As the Discovery Investigations deal primarily with whales, and Liitken's papers 

 are not readily accessible in many libraries, no excuse is needed for introducing here 

 descriptions and figures of the species represented in the collection. 



The family contains four genera: Cyamus, with type mysticeti, Liitk. (= ceti, Linn., 

 which, however, is better rejected as it is a composite species) from the Northern Right 

 Whale; Platycyamus, Liitk. 1873, with type thompsoni, Gosse, from the Bottlenose 

 (Hyperoddon) ; Paracyamiis, Sars 1895, with type boopis, Liitk. ; and Isocyamus, Gerv. and 

 Bened., with type delphi, Guer. 



Mayer (1890, p. 146) has shown that the embryo of nodosus has a well-developed palp 

 on the maxilliped, whereas in the adult the palp is rudimentary. Chevreux (1913, p. 183) 

 has determined the same phenomenon in erraticus, and for this reason does not accept 

 Sars' genus Paracyamiis. Chevreux's argument if pushed to an extreme, i.e. attaching 

 greater importance to juvenile, larval, or ultimately ovarian, characters, leads ad 

 absurdum, and it seems legitimate and much more convenient to take the characters of 

 the adult as of greater importance in determining the limits of genera. The genus 

 Paracyamiis is therefore retained here. 



Genus Cyamus, Latr. 



Stebbing, 1910 a, p. 471 (references). 



Gnathopods 1 and 2 unequal. Antenna 2, 4-jointed. Maxilla 2 with outer lobes. 

 Maxilliped, palp fully developed in adult. Dactylus and unguis of gnathopod 1 evenly 

 tapering, the latter not distinct. Branchiae on segments 3 and 4, single or double, or 

 fasciculate (physeteris — for figure of latter see Lutken, 1893), straight or spirally coiled. 



Cyamus ovalis, R. de Vauz. (Fig. 170). 



R. de Vauzeme, 1834, p. 259, pi. viii, figs. 1-2 1. 

 Lutken, 1873, p. 267, pi. ii, fig. 4. 

 Stebbing, 1910 a, p. 472. 



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