Mr. W. H. Benson on Tanysiphon. 409 



provided with minute tentacula, but the orifice of the exhalant 

 siphon is naked. The small foot is hatchet-shaped, with the 

 posterior margin notched. Both the siphons and the foot are 

 wholly retractile, and highly sensitive. The foot is sometimes 

 extended and tongue-shaped, but generally of the outline repre- 

 sented.^^ 



The specimens received in spirits show that the mantle is 

 closed at the basal edge, presenting narrow openings at either 

 extremity for the passage of the siphonal sheath and foot. The 

 suture is nearly straight, scarcely undulate. The foot is thick 

 and cartilaginous, broad, and with a pit or depression at the 

 anterior end, and laterally hamate, or bent like the crook of a 

 walking-stick, the point being towards the hinge-side, and the 

 hinder edge straight, not concave. 



For comparison with Novaculina, I copy the following extracts 

 from my paper pubhshed at Calcutta, in the ^Gleanings in 

 Science' for February 1830, a work edited by the late Captain 

 Herbert. It was the precursor of the ^ Journal of the Asiatic 

 Society,' and is now very scarce. Reference to that memoir 

 would have probably prevented the form from being confounded 

 as a subgenus under the awkwardly-named Solecurtus of Blain- 

 ville, and from being regarded by several recent authors as 

 merely an estuary shell. The living specimens, from which I 

 drew the characters, were procured in large communities by 

 digging in a strong slaty clay in the banks of the River Jumna, 

 at Humeerpore in Bundelkhund, one thousand miles from the 

 sea by the river line. The dead shells had previously occurred 

 to me in the Ganges, and in the Goomty at Juanpore, between 

 Lucknow and Benares. 



The branchial siphon is ciliated in Solecurtus ; in Novaculina 

 both the siphons are destitute of cilia. 



Extracts from Description 0/ Novaculina, pp. 63 & 64. 



" Animal. Mantle with the basal edges united, forming a 

 tube which encloses the animal, longitudinally constricted at the 

 suture. Foot proceeding from the anterior extremity, short, 

 thick, cylindrical, and very muscular ; enlarged at the extremity 

 into a disk with a convex surface, the plane of which is at right 

 angles with the axis of the foot and shell. Siphons separate, as 

 long as the shell when fully extended; the anal one, or that 

 nearest the hinge, half the thickness of the other; apertures 

 constricted, not ciliated.'"' 



" As in the Solenacese, the edges of the mantle are soldered 

 together at the base, forming a tube which confines the animal 

 and gives more support to its muscular foot, the exertions of 



