Ill 



DESCRIPTION OF THE ANIMAL OF TRIGONIA, 

 FROM ACTUAL DISSECTION ' 



Zoological Society Proceedings, vol. xvii. 1849, //. 30-32, also in Annals and 

 Magazine of Natural History, vol. v. 1850, pp. 141-143 



The accompanying account of the animal of Trigonia was for- 

 warded to me by Mr. Huxley, Assistant-Surgeon to the Rattlesnake, 

 now surveying in the Eastern and Australian Seas, under the able 

 command and scientific zeal of Captain Owen Stanley. 



The great number, beauty and geological importance of the species 

 of this interesting genus have made especially valuable a knowledge 

 of the structure of its animal. Quoy and Gaimard were the first to 

 give any account of it, and a figure and description of the animal of 

 Trigonia were published from their drawings and notes in the zoo- 

 logical division of the Voyage of the Astrolabe? Since then I am 

 not aware of this curious creature having been re-observed, though 

 much has been written respecting its systematic position. As in such 

 a case a verification of the evidence we possess, through a new and 

 accurate set of observations, is of almost as much importance as the 

 description of an unobserved animal, the Zoological Society may con- 

 sider Mr. Huxley's notes in the light of a valuable contribution to 

 malacology. 



Both accounts confirm the idea suggested by the shell of its 

 position among the ArcacecB, and its close afifinity with Niicula and 

 Area. The degree of union of the mantle-lobes, and the development 

 of siphonal tubes in this family, as among the neighbouring Mytilidcs, 

 is of generic and not sectional significance. 



^ The paper is l3y Prof. E. Forbes. The part headed Description of Trigonia is written 

 by Huxley. — Eds. 



^ Vol. iii. p. 476, Mollusques, pi. 78, f. 5. 



