293 
Of the four specimens three have their left tergum and scutum 
fixed, whereas the fourth (Fig. 41) has the right scutum and tergum 
fixed, the left plates movable. 
Carina and rostrum interlock by three ribs; the carina is a 
little pointed, whereas the rostrum has a rounded and little pro¬ 
minent apex. The movable tergum has only a strongly pro- 
nounced diagonal rib; two other ridges, which interlock with the 
Fig. 41. Verruca cristallina f. laevis ; 25 miles E. of Zamboanga. a specimen from the 
side of the movable scutum and tergum, h the same from the side of the fixed scu¬ 
tum and tergum, c movable tergum and scutum, d inside of movable tergum. 
[All figures x 8]. 
scutum, are only little pronounced. The movable scutum has 
four strong ribs articulating with the rostrum; only one rib inter- 
locking with the tergum, viz. that next to the diagonal rib, is 
more prominent. The fixed tergum and scutum have only 
rather feeble lines of growth; in the tergum a broad ala is devel- 
oped, whereas in the scutum a narrower radius is present, both 
with distinet lines of growth. 
The internal side of the movable plates is almost sculptureless. 
No ridge or myophore is seen in the fixed plates. 
The mouth feet are very characteristic (Fig. 42). In the man¬ 
di ble a fourth tooth is indicated just above the pectinate lower 
angle; the upper base of this fourth tooth is denticulated. The 
maxi 11a has one short and thick upper spine and at its lower 
side a longer but somewhat more siender spine. In the broad ex- 
cavation, which occupies about one half of the entire cutting edge, 
two minute thorns are seen in the middle; below the exeavation 
two larger and some smaller spines are present. The sides of the 
outer part of the blade are adorned with short hairs which are 
placed in groups of two or three. 
