GALEOMMA. 73 



byssal fissure, from which a fasciculus of fine filaments issues, 

 which fix the animal so firmly to whatever it is placed on, 

 as to require some force to detach it ; in fact, the hyssus is 

 discarded by being altogether withdrawn from the slit in the 

 foot whenever an attempt is made to remove the animal by 

 force; but though we repeated this operation several times, 

 the little creature did not appear to be injured or less lively, 

 but as soon as it had crawled to some distance, we had the 

 good fortune to witness the formation of a new byssus, which 

 was effected by the discharge of a light green glutinous opake 

 matter from the fissure at the heel of the foot, which by its 

 ponderosity resolved itself into delicate fibrous filaments that 

 instantly adhered to the saucer : we detached the animal 

 several times, the byssus was always left, and a new one 

 formed. On leaving it for the night, in a marked position, 

 we found in the morning that it had detached itself by aban- 

 doning the byssus, and formed another at a considerable 

 distance. 



The animal marches with great vivacity, by flattening the 

 valves into the form of a circular disk ; it then, by the foot, 

 aided by the muscular margins of the mantle, makes rapid 

 progression. We are unable to speak of the branchiae j or the 

 particular character of the palpi or labia, and whether they 

 are distinct free pendulous palpi, or the drooping folded labia 

 of the Nucula-, nor is it clear, from M. Mittre's or Dr. 

 Philippics account, which of the two forms is the true one. 

 I blame myself greatly for my inattention to these points 

 when I had it in my power to verify them ; they have now 

 become important, either to support or impugn my reasons 

 for placing Galeomma in the family of the Arcada. But if 

 even the palpi or labia should show a difference from the usual 

 structure of those organs in the Arcada, it must be considered 

 as an aberration of an aberrant genus ; however this may be, 

 abundance of facts will be adduced to justify the removal of 

 Galeomma to the Arcada. My memory will not allow me to 

 say anything of the siphonal apertures, or of the long anterior 

 stylet. We have twice taken this beautiful creature alive in 

 the coralline zone off Budleigh Salterton, Devon. 



