12 JURASSIC RHYNCHONELLIDS 
taxa concerned, suggest that they were attached to algae or sponges and consequently 
easily drifted long distances. While the normal mode of life may well have been the 
same as that of Lacuwnosella, the small size and delicate nature of the test obviously 
made it much easier for them to be transported over considerable distances and 
account for their appearance in such a diverse range of habitats. 
Distribution of Kimmeridgian 
rhynchonellid genera 
Fic. 4. Ac=Acanthorhynchia ; La=Lacunosella ; Mo=Monticlarella ; Rh=Rhynchonella ; 
“Rh ’’=“ Rhynchonella’”’; Se?=Septaliphoria? ; To=Torquirhynchia. 
