ON A LARGE PENELLA-SPECI ES. 229 



NOTE IX. 



ON A LARGE FENELLA-^mClf.^ FROM THE 

 MOLUCCAS 



Dr. R. HORST. 



(With 3 figures). 



Mr. J. W. van Nouhuys, Commander of the Government- 

 Marine in Dutch India, presented to the Leyden Museum 

 some pieces of the skin of a big fish (Selachian ?), caught 

 in the Moluccas, that are beset with several specimens of 

 a large Penella ; in like manner upon different points of 

 the body of these parasites, individuals of the well-known 

 Cirripede Conchoderma virgatum Spengl. have fixed them- 

 selves. It is not an easy task to state to what species of 

 Penella our specimens may belong, for though Steenstrup 

 and Lütken ') have given us a detailed description and exact 

 figures of four species of this genus, viz. P. sagitta, varians, 

 exocoeti and crassicornis, and afterwards Koren and Daniels- 

 sen published a rather elaborate paper on a Penella from 

 Balaenoptera rostrata ^), there reigns as yet a good deal 

 of uncertainty about the specific characters of several other 

 described specimens ; moreover, as remarked by the first-named 

 authors in their description of P. varians^) »we know not 



1) Bidrag til kundskab om det aabne Havs Snyltekrebs etc. : Kongel. Danske 

 vidensk. Selskabs Skriften, 5e raekke, nat. og math. Afd. 5e bind, 1861, p. 408; 

 to the kindness of Miss Annie Jentink I owe a translation of this paper. 

 ' 2) Fauna littoralis Norvegiae, Hft. 3, 1877, p. 157, pi. XVI, figs. 1—9. 

 3) loc. cit. p. 414. This parasite was found upon a fish, Conjphaena sp.. 



Notes from the Leyden ÜMuseuin, 'Vol. XX VI. 



