168 VERMETID.*. 



Subgenus Yermicularia, Lam., 1799. 



Shell free, in its early stage regularly coiled like a TuryHtella ; 

 subsequentl}' uncoiled, the tube variously twisted or more or 

 less straight and prolonged. Operculum size of the aperture. 

 Carboniferous — living. Tropical and subtropical. 



There is apparently no other distinction between the shells of 

 Vermicularia and Burtinella, except that the latter are coiled 

 in a broad, largely umbilicated cone ; Tubidostium has a con- 

 tracted aperture. Often called VermiciiUis, Lister. 



Genus SILIQUARIA, Brug., 1189. 



Animal with rudimentary pedal tentacles ; mantle slit along 

 the branchial cavitj'. 



Shell tubular, at first spiral, afterwards protracted and irregu- 

 lar ; tube with a longitudinal fissure, which is sometimes simple, 

 sometimes formed by a series of perforations ; often both varieties 

 exist in the same specimen ; a[)erture circular, without internal 

 septa or lamellae. Operculum corneous, subcylindrical or 

 conoidal, formed of a spirally- rolled band, with ciliated margin; 

 axis of the cone filled up internally by a series of spiral radiat- 

 ing cells (PI. 48, figs. 9, 10). Mediterranean Sea, W. Africa, 

 Tropical Pacific Ocean. 



Fossil, 20 sp. Tertiary-, one species from the upper creta- 

 ceous. The typical species, as well as several others, occur 

 imbedded in sponges. 



Tenagodus, Gueltard, 1774, is the same, but the genus is much 

 better known under its later name. 



Fischer proposes the following divisions, based on distinctions 

 in the branchial slit. 



Section Siliqtjaria {sensn fifricfo). 



Slit continuous, open. 

 Section Pyxipoma, Morch, 1860. 



Slit closed hy a lamella, but not filled up outside, open near 

 the mouth. 



Section Agathirses, Montfort, 1810. 



Slit composed of numerous isolated holes. 



