FORAMINIFERAN AND OTHER CORALS 187 



Ramulina. — One of the most remarkable results of the 

 recent oceanographic investigations has been the revelation 

 of the extraordinary variation of the constitution of the 

 sea-bottom in areas situated a few miles from the coast-line. 

 There are various designations given to express the nature 

 of these deposits, all of them more or less vague and inde- 

 terminate — such as " mud," " sand," " shell," " gravel," 

 " rock," and " coral." In the hope of giving some assistance 

 to those who wish to use a more precise designation to a 

 so-called " coral " sea-bottom deposit, a description is given 

 in this book of various kinds of coral which play an important 

 part in the formation of 

 such deposits in various 

 parts of the world. 



One of the most in- 

 teresting of these is the 

 deposit discovered by 

 Herdman along the 100 

 fathom line about 12 

 miles south of Galle in 

 Ceylon. In this locality 

 the dredge brought up Fig. 95. 



f 1 From Ceylon. Nat. size. 



masses of a calcareous 



structure from |- to over 2 inches in diameter, which was 

 named by Dakin Raiinilijia Jierdmani. Unfortunately noth- 

 ing is known for certain about the living organisms that 

 form these calcareous structures, but there are sufficient 

 reasons for believing that they are Foraminifera. 



" They consist of a mass of anastomosing calcareous tubes 

 inextricably commingled and assuming two principal forms 

 of growth. Many specimens show a long series of globular 

 segments, arranged irregularly, and opening directly into 

 one another by large openings. These globular chambers at 

 intervals give off numerous radiating straight tubes varying 

 in length from quite small outgrowths to 1-25 centimetres 

 with a diameter of 1-5 mm. to 2 mm. These straight portions 

 may run in the same direction, separating but little and 

 becoming compact, or they may diverge and radiate from 

 a common centre. Eventually they reach either the 



-Ramulina herdmani. 



