ON THE SHETLAND CRUSTACEA, TUNICATA, ETC. 271 
the last two combined, Telson subequal to the long peduncle of lateral 
appendages, lageniform, gradually tapering from near the base to the 
extremity, about twelve spines on each side; terminal spines not larger 
than preceding. Lateral appendages with long and slender peduncle, 
with about 25-30 spines on the inner margin ; inner ramus not half so 
long as peduncle ; first joint equalling in length the two others; inner 
margin furnished with spines of similar character to those of peduncle, 
eight on first joint, three on second, four on last; the spines are peculiar, 
having a minute cilium springing from them at half their length: outer 
ramus longer than inner, ending in 3-4 long spine-like sete; margins 
almost naked, only having very few scattered sete. 
Male wholly deyoid of spiny armature on cephalothorax and pleon, 
First joints of first and second legs spinose. ‘Telson with fewer (about - 
eight) and much more slender lateral spines, and the terminal spines 
considerably larger than the others, Lateral appendages nearly as in 2, 
but the branches longer, the inner more than half length of the peduncle. 
Length half an inch. 
This seems to be the commonest species in our seas. It is nearly 
allied to D. Rathkii, but the cephalothorax is shorter and more tumid, and 
free from spines. 
Shetland and Durham coast (A. M. N), Moray Firth (Mr. T, Edward). 
Diastylis lamellata, Norman, Brit. Assoc, Report, 1866 (1867), p. 200. Two 
specimens, St. Magnus Bay. 
spinosa, n, sp, Male.—Pereion, viewed laterally and dorsally elongated 
ovate; carapace toothed in the latero-anterior margin, and having a crested 
line passing from behind, yery near to and subparallel with the inferior 
margin, which curving round in front meets the crest which comes from 
the opposite side at a short distance behind the rostrum; this crest, 
throughout the greater part of its length, is composed of little flat 
plates, which lie close against each other; in front, however, the line is 
broken up into distinct and separate spines. Rostrum with rows of small 
spines on each side; a slight central carina on the carapace, Segments of 
pereion smooth, not spined; last segment produced backwards laterally into 
much produced and acute processes. Pleon having each of the first five 
segments furnished with three more or less developed longitudinal rows 
of spines on the back, and two at the edges of the underside; the hin- 
dermost spine of each row the most developed. Sixth segment un- 
spined. Superior antenne much developed; peduncle long, last joint 
x furnished with a dense brush of auditory cilia; filaments long. First 
joint of last gnathopods and of all the pereiopods with strong spines. 
First pereiopods with the antepenultimate joint extending beyond the 
rostrum; penultimate joint equal in length to third and fourth com- 
bined, last joint subequal to fourth. Second pereiopods having first joint 
strongly spined, second very short, fourth long and unusually slender. 
First pleopods with basal joint and two very unequal branches ; second 
with two branches of nearly equal length, but one with more numerous 
and much longer plumose sete than the other; infero-posteal margin of 
second segment of pleon with a row of (six) long plumose sete; plu- 
mose sete under the third and fourth segments. Telson suddenly bent 
downwards at a short distance from the base, gradually attenuated, 
much produced, but not as long as the long peduncle of uropods ; twelve 
pairs of long, slender, lateral spines; terminal spines rather stouter. 
Inner margin of peduncle of uropods with numerous spines, with closely 
