ON THE SHETLAND CRUSTACEA, TITN1CATA, ETC. 271 



the last two combined. Telson stibequal to the long peduncle of lateral 

 appendages, lageniibrm, 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 setae ; margins 

 almost naked, only having very few scattered setae. 



Male wholly devoid 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 5 , 

 but the branches longer, the inner more than hall' length of the peduncle. 

 Length half an inch. 



This seems to be the commonest species in our seas. It is nearly 

 allied to I). Ratlikii, but the cephalothorax is shorter and more tumid, and 

 free from spines. 



Shetland and Durham coast (A. M. IN"), Moray Firth (Mr. T. Edward). 



Diastijlis 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, very 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 antennas much developed ; peduncle long, last joint 

 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 setae than the other ; infero-posteal margin of 

 second segment of pleon with a row of (six) long plumose setae ; plu- 

 mose setae 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 



