434 



THE WATEEING-POT SHELL. 



The third figure represents another species, the SWORD-BLADE EAZOE-SHELL, with the ends 

 of the siphon- tubes just protruding from the extremity. 



IN the next family, called Gaper Shells, because the valves when closed do not unite 

 completely, but leave a moderately wide aperture at the hinder part, the shell is strong, 

 thick, and opaque ; the foot is comparatively small, and the siphons are united and 

 retractile. 



The GAPER SHELL inhabits sandy and muddy 

 shores, and is especially fond of frequenting the 

 brackish waters of river-mouths, where the streams 

 are sure to bring with them a soft deposit of mud 

 and sand. The species which is represented in 

 the engraving burrows nearly a foot in depth into 

 the sand, and is able to breathe and gain sub- 

 sistence by the long siphons, which just protrude 

 above the surface. In looking at this animal, and 

 observing its habits, the entomologist is forcibly 

 reminded of the manner in which the rat-tailed 

 maggot, i.e. the larva of Eristalis tenax, the 

 great bee-like fly, with enormous eyes, is in the 

 habit of hovering for a moment over a flower or 

 leaf, settling for a moment, and then darting off 

 again with lightning speed. Like the Gaper 

 Shell, this larva spends its life deeply buried in the 

 mud, carrying on the business of respiration by 

 means of a long tube which, like the siphon of 

 the mollusc, can be retracted or extended at will. 



The Gaper Shell is much sought after in 

 many places as an article of food, not only by 

 man, but by birds and beasts, such as the walrus 

 and the blue fox. 



THE nearly cylindrical shell seen lying on the 

 ground in the front of the illustration on the op- 

 posite page is the WATERING-POT SHELL, a curious 

 creature found in some of the hotter seas. 



This species is a good example of a family 

 termed the Gastrochsenidse, in which the valves 

 are thin, gaping, and when adult, often connected 

 with a rather long calcareous tube, as in the 

 present instance. 



The Watering-pot Shell derives its name from the 

 curious perforated disc which closes its lower ex- 

 tremity, and bears no small resemblance to the 

 rose of a watering-pot. In allusion to the same 

 peculiarity, the French writers call the animal by 

 the name of Arrosoir. All the species are bur- 

 rowers, some into coral, some into stone, some into 

 shells, and others into sand, as is the case with 

 the creature which we are now examining. From 



the other end of the tube the siphons can be protruded to some extent, and with- 

 drawn when the animal is alarmed. 



One species belonging to this family, the Gastrochoena modiolina, has been known 

 to drive its burrow fairly through some oyster-shells into the ground below, and then 

 to make a permanent home by cementing all kinds of materials into a flask-like case and 

 fixing its neck into the perforated oyster-shell. 



GAPER SHELL. Mya arendria 



