ISOPODA. 
27 
ventral margin is nearly completely occupied by the same highly specialised setae. 
Here they graduate in size to the distal extremity, where they rather quickly become 
much larger than elsewhere. These setae (fig. 3) consist of a shaft with very finely 
granular contents, the shaft tapers and ends in a blunt point, which in certain aspects 
appears to be an elongated knob. Both margins are fringed with very delicate flat teeth, 
very close, in fact contiguous to one another. These appear to be set on the shaft 
at an angle so as to form the limbs of a V, of which the shaft forms a very broad 
base. The ventral margin of the second joint is very minutely dentate. None of the 
authors previously cited deal with this appendage in any detail. Eights describes 
the left mandible as having “ two corneous teeth, placed one within the other, that 
on the right contains but one ; they are convex externally and internally concave, 
with a small foramen at their base.” This latter statement I do not understand. As 
regards the palp, he states the two basal joints are subequal in length and the 
terminal one about half the size. Dr. Studer states that the cutting edge is divided 
into two ridges and bears no teeth, but only sharp undulating edges. This figure 
is not good ; he omits almost all the setae on the terminal joint of the palp, but in 
the comparative sizes of the joints they more closely resemble the ‘ Discovery ’ 
specimens. The only reference I have seen to the highly specialised setae is contained 
in Dr. Pfeffer’s description of S. septemcarinata ( 11 ), and he figures them for that species 
as being plumose to within a short distance of the enlarged end. 
The first maxilla (fig. 4) consists of two lobes. The inner one is very small and 
delicate, the outer one large and strong. The inner one is irregularly ovoid upon a 
short peduncle, the outer one is stout and slightly curved. Its cutting edge is hollowed 
out to some extent, and the margin is fringed with stout spines of variable length, but 
the largest are most anterior. In the specimen examined there are eleven of these. 
The dorsal margin of this joint is covered with very minute teeth, which are replaced 
by simple setae about the middle of its length. 
The second maxilla (fig. 5) is more delicate in structure, and comprises a thin but 
broad inner lobe, rounded distally and there provided with upwards of thirty specialised 
setae. About two-thirds the length of this lobe there arise externally two lobes of 
approximately equal size. It would, perhaps, be correct to say a single bifid lobe. 
Each of these lobes is armed distally with two stout specialised setae, similar to, but 
much stronger than, those of the inner lobe. The setae are all pedunculate. A central 
core runs continuously through the peduncle and shaft, and the latter is covered with 
a number of very minute but stout spines. 
The maxilliped (fig. 6) consists of a short but very broad sub-triangular plate, which 
carries the large masticatory lobe, and an approximately rectangular epignath. The 
inner margin of the masticatory lobe is straight, rounded towards the base, where 
there is a group of rather long simple setae, and a few other small ones are scattered 
along it. The anterior margin is nearly straight, and bears a stout tooth near each 
angle. The outer tooth is situated in rather a deep depression. The outer margin 
