442 
terminates in a seta; the length from the base to the tip of the 
seta is about equal to the two distal antennal joints together. From 
the basal posterior edge of the plate originates another plate, which 
is very small, triangular and terminates in a single seta; this plate 
is shown more highly magnified in fig. 9. The maxillulæ are inserted 
close to the base of the maxillæ. 
The Mazxillæ (maxillæ of the second pair or first pair of 
maxillipeds, auct.) consist of two parts (fig. 4, 4). The basal portion 
is a single joint about as long and thick as the six proximal joints 
of the antennulæ. The second part is a little longer than the basal 
joint, slender, looking nearly as an exceedingly thick seta, tapering 
towards the acute end, and its distal half is gradually strongly 
curved, forming a hook. At a short distance from the base this 
part is divided into two joints by a very oblique articulation. As 
to the morphological interpretation of the maxillæ I refer to p. 149 in 
the work of Giesbrecht mentioned below. These appendages are 
strong instruments most probably used by the animal for anchoring 
itself; auxiliary organs for the same purpose are the antennæ and 
especially the maxillipeds. 
The Mazxillipeds (figs. 3 and 4, i; fig. 10) are slender and very 
long, from the base to the end of the terminal claw about one 
fourth longer than the antennulæ. As the maxillæ they may be 
divided into two parts. The basal part is one slender joint which 
is mot fully one half of the whole appendage; it has been examined 
form various sides, but it was impossible to detect any division 
into two joints. The distal part of the maxillipeds consists appa- 
rently of three joints; the proximal one is very short, the two others 
nearly equal in length. The second of these joints is very slender 
and has on the inner part of the end a thin and rather short seta; 
the third joint, which is shaped as a robust, a little curved seta, is; 
according to Giesbrecht, not a real joint but a terminal hook. — 
The maxillipeds are inserted at some distance from each other; 
fig. 4 shows their insertions and besides those of the other appen- 
dages of the head in their relative position. 
