pteropoda. ^..53 



Section B. — Gymnosomata, B1. 



Animal naked, without mantle or shell ; head distinct ; £ns 

 attached to the sides of the neck ; gill indistinct. 



Family III. — Cliidje. 



Body fusiform ; head with tentacles often supporting suckers ; 

 foot small, but distinct, consisting of a central and posterior 

 lobe ; heart opistho-hranchiate ; excretory orifices distant, on the 

 right side; lingual teeth (in Clio) 12.1.12, central wide, denti- 

 culated, uncini strongly hooked and recurved. 



Clio (L.),* MiiUer. 



Etymology, Clio, a sea-nymph. 



Synonym, Clione, Pallas. 



Type, 0. borealis, PI. XIY., Pig. 45. (C. caudata, L., part.) 



Head with 2 eye tubercles and 2 simple tentacula; mouth 

 with lateral lobes, each supporting 3 conical retractile processes, 

 furnished with numerous microscopic suckers ; fins ovate ; foot 

 lobed. In swimming, the Clio brings the ends of its fins almost 

 in contact, first above and then below. (Scoresby.) 



Bistrihution , 4 species. Arctic and Antarctic Seas, Norway, 

 India. 



Suh-genus ? Cliodita (fusiformis), Quoy and Gaimard. Head 

 supported on a narrow neck ; tentacles indistinct. 4 species. 

 Cape, Amboyna. 



PNEUMODERMOisr, Cuvier. 



Etymology, Pneumon, lung (or gill), derma, skin. 



Type, P. violaceum, PI. XIY., Pig. 47. 



Body fusiform ; head furnished with ocular tentacles ; lingual 

 teeth 4.0.4 ; mouth covered by a large hood supporting two 

 small, simple, and two large acetabuliferous tentacles, suckers 

 numerous, pedicillate, neck rather contracted ; fins rounded ; 

 foot oval, with a pointed posterior lobe; excretory orifice 

 situated near the posterior extremity of the body, which has 

 small branchial processes, and a minute rudimentary shell 



* This name was employed by Linneeus for all the Pteropoda then known; his 

 definition is most suited to the " northern clio,'' probably tlie only species with which 

 he was personally acquainted. The first species enumerated in the Syst. Nat. is 

 C. caudata, and reference is made to an indeterminable figure iu Brown's Jamaica, 

 and to Marten's account of the Spitzbergen mollusc (C. borealis). In cases like this 

 the rule is to adopt the practice of tlie next succeeding natui'alist who defines tho 

 Umits of the group more exactly. 



