238 A HISTORY OF RECENT CRUSTACEA 
pair of trunk-legs are uniform in length, while in the 
other five genera they are unequal. Chlorotocus, however, 
has the wrist of these legs two-jointed, while in Dorodotes 
it is six-jointed. The ‘palp’ of the mandibles is two- 
jointed in Chlorotocus, undescribed in Dorodotes, three- 
jointed in the other five genera. 
Panddlus, Leach, 1814, has the ‘anterior portion of 
the carapace carinated and produced to a long rostrum 
that is armed on the dorsal or upper surface with movable 
spines, intermingled with hairs, and on the lower surface 
with fixed and rigid teeth.’ Also, the first pair of antennze 
are not longer than the carapace, and the spine on the 
outer margin of their basal joint is obtusely pointed. Two 
British species belong to this genus, Pundalus Montagu, 
Leach, which has priority over the more generally used 
name, annulicornis, Leach, and Pandalus brevirostris, 
Rathke. There are numerous other species in various 
parts of the world, among which Pundalus narwal, Milne- 
Edwards, in the Mediterranean, exceeds a length of five 
inches. Pandalus Montagu, though its usual length is 
given by Bell as from two to two and a half inches, is said 
by 8S. I. Smith to attain a length between four and five 
inches off the coast of the United States. 
Pandalopsis, A. Milne-Edwards, 1888, is most ob- 
viously distinguished from Pundalus by having the flagella 
of the first antenneze much longer than the carapace. The 
other genera are distinguished by some minute and curious 
characters, for while the frontal crest and rostrum of 
Pandalus are armed on the upper surface with movable 
spines only, in Nothocdris, Spence Bate, 1888, the dorsal 
crest has several spines that articulate in sockets, and 
several teeth that are fixed and rigid, but in Plesionika, 
Spence Bate, 1888, and Heterocarpus, A. Milne-Edwards, 
1881, there are teeth only, and no movable spines. In 
Plesionika, as also in Nothocaris, the spine on the outer 
margin of the basal joint of the first antennz is large and 
pointed, but in Heterocarpus it is said by Spence Bate to 
be rudimentary ; yet he identifies with the type species, 
Heterocarpus ensifer, A. Milne-Edwards, the Heterocarpus 
