REPORT ON THE PTEROPODA. 49 



3. Clione flavescens, Gegenbaur. 



1855. Clio flavescens, Gegenbaur, Untersuchungen uber PLeropoden und Heteropoden, p. 73, 



pi. iv. fig. 15, A, B. 

 1875. Clio aurantiaca (larva), Fol, Sur le developpement des Ptdropodes, Archives d. Zool. 

 exper., s<5r. 1, t. iv. p. 178, pi. x. fig. 10. 



Body of moderate length, and terminating behind in a point (quadrangular, ac- 

 cording to Gegenbaur). The visceral mass only extends to the middle of the body. 



Head rather wide (in Gegenbaur's figure the nuchal tentacles are distinguishable). 



Foot. — Anterior lobes rather wide, pointed behind ; posterior lobe rather long and 

 pointed. 



Fins wide at the base, but like those of Clione limacina. 



Buccal Appendages. — They have not been described, and Professor Gegenbaur wrote 

 me that the type specimen of this species no longer exists. But from the larva, it is 

 known that Clione flavescens possesses two pairs of cephaloconi, as in the foregoing 

 species. 



Radula. — Unknown in the adult ; in the larva, there are 2 : 1 : 2 teeth (Fol) 1 ; (in the 

 adult the radula probably possesses twice or three times as many lateral teeth). The 

 median teeth resemble those of Clione limacina, except that they possess a small median 

 denticle. 



Hook-sacs rather short in the larva. 



Colour. — The skin is transparent with a yellowish reflection ; the visceral mass has a 

 yellow tint. 



Length. — About 22 mm. 



Habitat. — Messina (Sicily). The first " Preisverzeichniss" of the zoological station 2 

 mentions " Clio flavescens" from the Gulf of Naples, but the form there obtained was 

 Clionopsis krohni. Clione flavescens has only been found at Messina, once in the adult, 

 and twice in the larval state. 3 



It is a true Clione, as much by the shape of the body and foot as by the absence of 

 gills. Bronn was therefore wrong in saying that only Clionopsis was found in the 

 Mediterranean Sea. 4 



Observation. — I consider " Clio aurantiaca," which Fol thought " probably adult," as 

 the young of Clione flavescens. 



Notwithstanding that it has been seen to lay eggs, "Clio aurantiaca" is not an adult. 

 It hardly reaches 2 mm. in length, and has still all the three ciliated rings ; besides its 

 radula has a larval formula. 



1 Sur le developpement des Ptdropodes, Archives d, Zool. exper., sdr. 1, t. iv. p. 179. 



2 Mitth. axis d. zool. Stat, zu Neapel, Bd. i. 



3 Besides Fol, J. Miiller, Ueber verschiedene formen von Seethieren, Archivf. Anat. u. Physiol, p. 70, 1854. 



4 Die Klassen und Ordnungen des Thierreichs, Bd. iii. p. 639. 



(zool. chall, exp. — part lviii.— 1887.) Mmm 7 



