258 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



XXIX. 



NOTES ON GASTEROPTERON MECKELII, 



KOSSE. 



BY EDGAR A. SMITH, F.Z.S. 



[Read 29th April, 1890.] 



The Rev. J. E. Somerville, B.D., has recently 

 presented to the British Mviseum a specimen of 

 Gasterojoteron Mechelii, which he dredged a short 

 time since at Mentone in 30 fathoms. This is 

 especially valuable to the Museum, being the first 

 example of this mollusk in the collection. 



This remarkable Tectibranchiate Mollusk occurs in 

 various parts of the Mediterranean, and has not 

 yet been discovered beyond that region. It is usually 

 found on sandy bottoms at a depth of from 20 to 

 30 fathoms, although occasionally it affects shallower 

 water. It has also been asserted that it has the 

 power of floating at the surface. Its food appears 

 to consist of Foraminifera and the larval forms of 

 various invertebrate organisms. It progresses by a 

 flapping movement of the lateral pedal lobes, instead 

 of crawling like most other gastropods. These lobes 

 of the foot recall to mind the appearance of certain 

 Pteropods, and this resemblance induced early 

 naturalists to associate Gasteropteron with that 

 class. 



In a living state the body and foot-lobes of this 

 curious animal are of a vivid red or orange-red 

 colour, the lobes being usually marked beneath with 

 a few scattered white spots and ornamented with 

 a pale or bluish border. The head is somewhat 

 triangular, obtuse in front and pointed behind, and 

 exhibits no trace of eyes or tentacles. Although no 



