PLATE IV. 
1. Terebratula conf. carteri, Davidson, p. 18; a specimen with the beak of the 
neural valve somewhat imperfect; East of 0la2Mudy ; Arrialoor grouj). 
17. Terebr.\tula biplicata, Sowerhy, p. 19. 
Figs. 2-4 and 10-13 represent the most tyjjical form with a thick, conspicuously 
incurved beak; all the specimens are from the neighbourhood of Midloor, 
Arrialoor group; in fig. 10 the biplication is scarcely traceable, in 11 it is 
slightly indicated, in 12 it is slight, but distinct, in the remaining four 
specimens it is well marked. 
Figs. 0-9 represent the variety named Karapaudiensis, p. 20, distinguished by an 
elongated form and a thinner beak ; in fig. 9 the biplication is absent, in fig. 7 
scarcely indicated, in figs. 5 and 8 distinct ; fig. 6 is the inner view of a portion 
of hsemal valve ; all specimens are from near Karapaudg ; Arrialoor group. 
Figs. 14-17 represent the variety Dutempleana (see j). 20); in fig. 15 the biplica- 
tion is not marked, in 16 it is very slight, in 17 very strong, but comparatively 
less so in the large specimen represented in fig. 14; this shows that the amount 
of biplication is independent of size and age ; the last specimen is from Olapaudg, 
Arrialoor group ; the other specimens from between Andoor and FeragJtoor in 
Trichinopoly group. 
