FAMILY 1. TUBICOLA. 33 



Family 1. TUBICOLA. 



Testa vagina testacea tubulosa munita, vel libera, vel vaginae pariete 

 partim aut totaliter incrustata. 



The animal of the Tubicola is furnished with a small bivalve shell, 

 either entirely free, or partially or wholly imbedded within the sub- 

 stance of a testaceous tube. This tube does not appear to form an 

 immediate part of the organization of the animal, but merely an acces- 

 sory though important agent in protecting its inhabitant. 



The Tubicola are often found buried in wood, but are for the most 

 part lithophagous ; the holes and cavities in which they live are evidently 

 perforated by the animal, assisted no doubt by a powerful solvent secre- 

 tion from the glands, as they do not appear to be the result of mechanical 

 attrition. We refer the following five genera to this family : 



Aspergillus*. Gastroch^ena. 



Clavagella. Teredo. 



Fistulana. 



ASPER GILL UM, Bruguiere. 



Testa a?quivalvis, subaequilateralis, in pariete inferiori tubi testacei om- 

 nino conferruminata, umbonibus extra tubum subprominulis ; tubo 

 interne clauso, disco terminali poris minimis numerosis fissuraque 

 centrali perforato, margine tubulis minimis plerumque circum- 

 cincto ; superne elongato, plus minusve attenuato, pervio, mar- 

 gine plerumque reflexo, undulatim fimbriate 



The Aspergillum had long been a source of embarrassment to early 

 naturalists, who with Linna?us had, from the tubular appearance of its 



VOL. I. F 



