TEEEBEATULA. 385 



generally open ; and at the base rather acute, sometimes 

 gaping. Two muscular impressions approximate near the 

 centre in each valve. Mr. Cuming met with a considerable 

 number of the Lingula anatina during his cruize amongst 

 the Pliilippine Islands; he mentions that they are eaten 

 occasionally by the natives, but he did not consider them 

 as wholesome food. The fact of their having so long escaped 

 the notice of travellers may be attributed to their peculiar 

 mode of life — they live buried in hard sand, and may only be 

 dug out at low water. 



The genus Terehratula, from the extent of its geological 

 relations, has always been one of considerable interest, and is, 

 in fact, richer in fossil species than any other. The shell 

 differs materially from that of Lingula, and consequently 

 requires a brief description. It is inequi valve, inequilateral, 

 oval, or orbicular, adhering by a rather short fibro-gelatinous 

 tendon. The upper valve is produced at the apex, often 

 curved inwards, and perforated for the tendon, with a 

 single dentiform hinge-process on each side. Two slender, 

 shelly processes, generally recurved and bent, pertain to 

 the lower valve ; the muscular impressions are indistinctly 

 marked. 



Such are the varied arrangements made for the comfort 



