rORAMINIFERA OF THE ATLANTIC OCEAN 59 



studded with irregular exogenous granules. The septa of well- 

 developed typical shells are double." 



This is a very good general description of the species as it occurs 

 at its type locality at Rimini. The description should go further 

 however, and the series of figures given will illustrate the further 

 points. Figure 3 is of a megalospheric specimen with a large pro- 

 loculum, that has ten chambers, and although this is a young speci- 

 men, the characters show the smooth surfaces, and the sutures on the 

 ventral side without the ornamentation seen in older specimens. 

 Six chambers make up a whorl, and the central plug of the umbilical 

 area is not developed. The ending of the chambers on the ventral 

 side is somewhat similar to Discorbis. 



Figure 4 shows a specimen with a microspheric proloculum and 

 18 chambers. There are eight chambers in the whorl although but 

 six in the earlier stages. There is a definite development of the 

 central plug of the ventral side, but beading of the sutures is not yet 

 developed. 



Figure 5 shows a microspheric specimen that has 21 chambers, 

 nine making up the last-formed whorl. The central plug is already 

 somewhat ornate, and there is a tendency for the sutures to open up 

 and become beaded. 



Figure 6 shows a specimen with more chambers than the preceding, 

 probably microspheric but as the dorsal side is covered with secondary 

 shell material, it is difficult to make out the early chambers. The 

 central plug has become enlarged and the sides of the sutures on the 

 ventral side are decidedly beaded and fluted. There are 11 chambers 

 in the last-formed v/horl. 



Figure 7 shows an adult microspheric specimen in which the cover- 

 ing of the central part of the dorsal side of the test is carried much 

 further than the preceding. The ventral plug is broken into several 

 large bosses at the surface. The sutures are heavily beaded aud fluted. 

 The last-formed coil has 13 chambers, nearly double that of the younger 

 individuals. Specimens of this general form are very abundant at 

 Rimini. The difference in relative thicloiess of the test is also shown 

 in the peripheral views, the young stages being much thicker in 

 proportion than the adult. 



A comparison of these figures with those given by different authors 

 from various parts of the world will show the wide deviation from 

 this typical form. A study of fossil and Recent Rotalias related to 

 R. beccarii should prove useful as numerous varieties or species will 

 be found with definite distributions and the true R. beccarii will be 

 found to have a rather restricted area. 



This species is splendidly developed in the Adriatic and like others 

 of that region is also found along the coasts of western Europe. 

 Plate 13, figure 2 shows a specimen from the Belgian coast. I have 



