41 



as broad, reaching somewhat beyond the articulation of the exopod, with the distal half of the 

 lateral margins straight; along this distal half the lateral spines are closely set, and a number 

 of them are long, while between two long spines i, 2 or 3 short spines are found, the arran- 

 gement being so that near the distal end i small spine, a little more proximally 2 and finally 

 3 small spines are inserted in the intervals between the long spines; it may, however, be added 

 that frequently no small spine is found between the two (or three) most distal, large lateral 

 spines. The animals have a lateral pair of black, round spots on each abdominal segment and 

 besides black spots of various shape on the uropods and on the female marsupium. 



Length of the male 10 — 10.2 m., of the female 9.1 — 11.2 mm. 



Remarks. — This species differs from the other forms of this group and from the 

 forms of the preceding group by having" the endopod of the uropods reaching about or generally 

 exactly to the end of the exopod and by the well developed, black dots mentioned, while in 

 all other species of both groups such dots are nearly or totally wanting and the exopod of 

 the uropods conspicuously overreaching the endopod. — The differences mentioned in the 

 description as to the length of the pseudobranchial rami and the relative length of the modified 

 setae on the endopod of fourth pair of male pleopods are, in my opinion, not of specific value, 

 especially as it is possible to find specimens, showing a development of the spines intermediate 

 between those exhibited in figs, i/" and 1 /i. 



Distribution. — The Copenhagen Museum possesses this species from four localities, 

 viz.: Arabian Sea, lat. 9° N., long. 73° E., March 3, 1S72, H. Koch, i specimen; Bay of Bengal, 

 December 20, "Galathea" Expedition, 5 specimens; Indian Ocean, lat. 3°9'N., long. 84°44'E., 

 "Galathea", i specimen; finally China Sea, lat. I9°I4'N., long. ii6°6'E., June 18, 1846, 

 "Galathea", i specimen. These statements, together with some of the "Siboga" stations, show 

 that this species is frequently met with far from the coast in the open sea. 



21. Siriella anomala n. sp. PI. V, figs. \a — i /. 



Stat. 37. March 30/31. Sailus ketjil, Paternoster-islands. 27 m. and less. Plankton, surface. 



Numerous specimens. 

 Stat. 40. April 2. Anchorage off Pulu Kawassang, Paternoster-islands. 12 m. Townet. 16 specimens. 

 Stat. 41. April 3. Lat. 7°25'S., long. ii7°5o'.5 E. 96 m. From 10 m. to surface. 22 specimens. 



Description. — Shape of the body, frontal plate, eyes and male antennular peduncles 

 about as in S. inornata, excepting that the frontal plate is a little more produced, with the 

 distal part of its lateral margins more concave, than in the specimen of the latter species shown 

 in fig. 2a on PI. IV. Antennal squama very different in the two sexes; in the female it is 

 normal (fig. i b)^ a little more than three and a half times as long as broad, with the terminal 

 lobe much broader than long; in the male (fig. la) it is quite anomalous, elongated, more than 

 five times as long as broad, with the marginal denticle about at the middle of the squama, as 

 the outer margin between this denticle and the base is distinctly shorter than in the female, 

 while the terminal lobe is extremely elongated, more than three times as long as broad at the 

 base. Gnathopods (fig. i c) and thoracic legs (fig. i d) a little more slender than in 5. inornata, 

 otherwise nearly as in that species. 



SIBOGA-EXPEDITIE XXXVII. 6 



