44 
l. Diastylis Rathkei (Kreyer). 
(pi. sxxni, xxxxv). 
Cuma Rathkei, Kreyer, Nat. Tidsskr. Vol. 3, p. ol3, pi. 5, 6, figs 17—30. 
Syn: Cuma angulata , Kroyer (adult male). 
Specific Characters. — Female: Body more slender than in most other 
species of this genus, with the anterior division scarcely at all tumefied, and 
oblong in form. Carapace exceeding the exposed part of the trunk by about 1 /z 
of its length, and but slightly vaulted above; frontal lobe armed along the 
middle with a double row of strong, anteriorly-curving denticles, sometimes 
crossed by one or 2 imperfect transverse rows, lateral faces below the frontal 
lobe exhibiting a somewhat varying number of scattered small denticles; pseu- 
dorostral projection conically produced, horizontal; subrostral corners more or less 
distinct. Last pedigerous segment with the anterior edge coarsely serrate, lateral 
parts produced behind to rather large acute processes, extending almost to the 
end of the 1st caudal segment. Tail somewhat exceeding the length of the an¬ 
terior division, segments simple, without any spiniform projections. Eye rather 
small, though distinct. Superior antenna; not very slender, the peduncle scarcely 
reaching beyond the tip of the pseudorostral projection, 1st joint about the length 
of the other 2 combined, and armed at the end inside with a small denticle. 
First pair of legs scarcely longer than the carapace, basal joint equalling in 
length the remaining part of the leg, and denticulate in its distal part, the last 
3 joints of about equal length; 2nd pair with the terminal joint not much longer 
than the preceding one, both together scarcely exceeding half the length of the 
antepenultimate one; 3rd and 4th pair very strongly built and densely setiferous. 
Uropoda about half the length of the tail, outer ramus rather robust, being con¬ 
siderably larger than the inner, though scarcely exceeding half the length of the 
stem, and densely setiferous along the outer edge and the tip; inner ramus with 
the 1st joint fully as long as the other 2 combined, spinules of the inner edge 
about 11 in number (6 of the 1st, 3 of the 2nd, and 2 of the last joint), apical 
spine strong, mucronate. Telson rather produced, extending fully as far as the 
stem of the uropoda, its proximal thickened part comparatively short, scarcely 
occupying more than l /± of the length of the telson, distal part gradually attenuated, 
and armed on each side with numerous (about 15) spinules, apical spinules of 
exactly the same appearance as the lateral. Colour whitish, with a more or less 
distinct carneous tinge. Length amounting to 16 mm. 
Fern arks .—This form was first described by Ivroyer in the year 1841 as 
a species of the genus Cuma. The form subsequently recorded by the same 
