164 THREE CRUISES OF THE “BLAKE.” 
lata (Fig. 496), is frequently brought up in the globigerina 
ooze from depths greater than 400 fathoms. 
The group dates back to the jurassic, and 
seems to be a characteristic deep-sea type in 
all the oceanic basins. Ammodiscus tenuis 
(Fig. 497), taken by 
the “Challenger” off Fig. 496. — Thuram- 
Neat info” sa Y. 
fathoms, is a recent rep- 
resentative of a very common palozoic 
type of the carboniferous period. 
According to Brady, Cyclammina (Fig. 
498) represents in our seas the highest 
Pa raf m rs e type of arenaceous foraminifers. The 
muis, 4,9. rady.) i 5 
genus is characterized by the labyrinthian 
structure of the test (Fig. 499), and is abundant in depths 
below 100 fathoms in the West Indian region. 
Fig. 498. 89. Fig. 499. 20. 
Cyelammina cancellata. (Brady.) 
Most variable in the shape and structure of their shells are 
the Textularine. A very common type 
of the group is the cosmopolitan Tex- 
tularia sagittula (Fig. 500), which at- 
tains a length of 6 mm.; it has been 
dredged in the Atlantie in 2,675 fath- 
oms. Another abundant form, which 
Fig. 500. —Textularia sagi. dates back to the eretaceous, is the com- 
tula. 49. (Goàs) pact and thick-walled 7. trochus (Figs. 
