44 THE VOYAGE OF H.M.S. CHALLENGEK. 



Clione, 1 Pallas. 



1774. Clione, Pallas, Spicilegia zoologica, fasc. x. p. 28. 



1776. Clio, 0. F. Miiller (non Browne), Faunae danicse prodromus, p. 226. 



1825. Cliodita, Quoy and Gaimard (pars), Description de cinq genres de Mollusques, Ann. d. 



Sci. Nat., ser. 1, t. v. p. 74. 

 1840. Spongiobranchea, d'Orbigny (pars), Voyage dans lAmerique meridionale, t. v. p. 132. 



Characters and Description. — As in the family Clionidse, great confusion has existed 

 for a long time in regard to the cephalic appendages of Clione. In a paper on these 

 organs 2 I have shown that there may be distinguished : — 



(1) The buccal appendages or cephaloconi, inserted on the wall of the buccal 



cavity. 



(2) The true tentacles, situated on the external wall of the head, and numbering 



two pairs. First, the anterior, labial or oral pair, and second, the posterior, 

 nuchal or cervical pair. 



A great number of Gymnosoniatous Pteropods are described under the name Clione 

 (or Clio) ; but a considerable proportion of these forms are so little known, so imperfectly 

 and insufficiently described and figured, that it is impossible since the type specimens 

 have been lost to give a diagnosis of them, and to admit them into the nomenclature. 



I have found in the literature (after eliminating, of course, the Thecosomata bearing 

 the name Clio, which are more often called Cleodora) nineteen different names of Clione 

 (or Clio). 



Among these nineteen names there are : — 



1 . One given to a Mollusc of another group — 



(1) Clio amati, Delle Chiaje 3 = Gastropteron meckeli, Kosse. 



2. Names given to forms belonging to other genera of Gymnosomata — 



(2) Clio capensis, Eang = Notobranchasa sp. 



(3) Cliodita caduceus, Rang = Spongiobranchsea australis, d'Orbigny. 



(4) Clio mediterranea, Gegenbaur =Clionopsis krohni, Troschel. 



3. Names which are synonyms of other specific names of the genus Clione, as we shall 

 see further on — 



(5) Clio aurantiaca, Fol = Clione flavescens, Gegenbaur. 



(6) Clione borealis, Pallas = Clione limacina, Phipps. 



(7) Clio caudata, Gray (non Macdonald) = Cfr'ewe longicaudata, Souleyet. 



(8) Clione dalli, Krause= Clione limacina, Phipps. 



1 From Clio, a mythological name. 



2 The Cephalic Appendages of the Gymnosomatous Pteropoda, Quart. Journ. Micr. Sci., 1885, p. 493. 



3 Memorie sulla storia e notomia degli animali senza vertebre del Regno di Napoli, t. i. p. 52. 



