70 PROCEEDINGS OF THE ACADEMY OF [1889. 



THE BOEING-SPONGE, CLIONA. 

 BY JOSEPH LEIDY, M. D. 



Among the ocean debris of the neighboring Atlantic coast, shells 

 of the oyster, Ostrea Virginiensis, and of the clam, Venus mercenaria, 

 conspicuous from their being riddled with holes, are frequent. When 

 I first saw such shells I suspected that the numerous perforations 

 were due to an annelid or perhaps a boring mollusk. In 1856, 

 while at Beasley's Point, on Great Egg Harbor, New Jersey, I had 

 the opportunity of observing the shells of both dead and living oysters 

 drilled in the same manner and with the borings occupied by a living, 

 soft, yellow, silicious sponge. A notice of my observations on the 

 sponge, attributed to the genus Cliona, with its character, peculiar 

 habit, and incidental importance in the economy of nature, was pub- 

 lished the same year in the Proceedings of this Academy, Vol. VIII, 

 p. 162. 



Apparently the massive form of the same sponge, was previously 

 described by Desor, under the name of Spongla sulphurea, occurring 

 in Vineyard Sound (Proc Boston Nat, Hist. Soc, 184$, 68). 



Later, the sponge of the same locality was noticed by Prof. Ver- 

 rill as Cliona sulphurea, and is described as commencing in the con- 

 dition of a boring form on dead shells and subsequently growing into 

 masses six or eight inches in diameter (Rep, U. S. Fish Commission, 

 1873, 421). 



In Little Egg Harbor, in the vicinity of Beach Haven, N. J:, I 

 have observed the boring-sponge in various stages from the condition 

 in which it occupies the shells of oysters and clams with its sensitive 

 papillae and oscules protruding from perforations of the surface of 

 the shell, to variously massive forms enclosing at their base the rid- 

 dled shells from which they sprung. Sometimes I have observed a 

 mass enveloping a pair of open, perforated, shells of an oyster or clam 

 in which the shells were still united at the hinge. Often too, a massive 

 sponge envelops, together with its original cradle, fragments of 

 other shells, pebbles and sand. To the fishermen of Beach Haven, 

 the massive sponge is familiar under the name of Bay-pumpkin; 

 often growing to the size of one's head. 



In the oyster beds, the boring-sponge especially invades the upper 

 or more exposed shell, and the living oyster incessantly protects it- 

 self by the formation of new shell-layers. The sedentary habit of 



