KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 22. NIO 7. 201 



»The first three abdominal segments are of very large size, especially the first two, either 

 of which is as long as any three of the thoracic segments. The fourth abdominal segment is 

 much shorter and narrowed in front, so as to be freely movable under the much excavated po- 

 sterior border of the third. The fifth and sixth abdominal segments are very small, and the 

 latter is united without suture to the short accurately semicircular telson.» 



»The second of the thoracic appendages (= the first pair of perceopoda) is short and stout 

 and provided with a somewhat incomplete subchela. The third (= the second pair), longer and 

 somewhat slighter, has the subchela very well developed, the opposable prolongation of their 

 carpopodites (= the carpal process) being distinctly hollowed out for the reception of the cylin- 

 drical propodite. The remaining thoracic appendages are of the usual type, increasing regularly 

 in size to the seventh (= the sixth pair'), which is longest; the sixth and eigth being subequal. 

 The eigth (= the seventh pair) has its posterior border provided with a strong buttres-like plate. 

 Some of the posterior thoracic appendages are provided with gill-sacs, but I was unable to 

 satisfy myself as to their exact number and position in this stage of the animal, although they 

 are probably identical with those of the Hyperia-stage.» 



»The first three abdonanal appendages are subequal and on the usual amphipod plan. The 

 remaining three have long protopodites (= peduncles) and small equal rami, the first two being 

 subequal, while the last is a quarter shorter than the preceding two pairs. » 



»In swimming, it progresses by a series of jerks, lying on its side and moving in small 

 circles.» — — — 



»The present species is one of the commonest surface organisms of the Bay of Bengal, 

 and is especially so in the more truly pelagic portion of its area.» 



»I notice that the pelagic Lestrigoni are very generally credited with being parasitic on 

 medusae, etc. In the present species this is not the case. I have occasionally seen them 

 ensconced in the cavity of a Salpa, but believe this to have been an accidental circumstance, as 

 by far the larger number were captured swimming freely.» 



»The specimen figured was taken in the drift-net about 100 miles from land in the Bay 

 of Bengal, the depth of the water in the locality being 850 fathoms. Seven specimens were ob- 

 tained on this occasion and some hundreds have since been taken. » 



11. HYPERIA SIBAOINIS, TH. STEBBING, 1888. 



Diagn. Caput curtum, segmenta duo priora perasi longitudine a3quans. Segmenta omnia perm libera, 

 primum longissimum. Carpus pedum percei primi paris paullo dilatatus et productus, pro- 

 cessum formans tertia parte marginis posterioris metacarpi breviorem. Carpus pedum secundi 

 paris paullo dilatatus et productus; margo anterior processus carpalis dimidio marginis 

 posterioris metacarpi paullo brevior. Metacarpus pedum primi et secundi parium spinas 

 . binas margini anteriori affixas gerens; margo posterior serratus, dentibus simplicibus; dac- 

 tylus longus. Pedes tertii ac quarti parium pedibus parium duorum prajcedentium longi- 

 ores; carpus metacarpusque serrati, carpus spinam singulam gerens; dactylus longissimus. 

 Pedes parium trium ultimorum duobus prascedentibus longiores; tibia, carpus, metacarpusque 

 serrati; carpus pedum quinti ac sexti parium tibia longior. Latera segmentorum plei post 

 angulata. Pedunculus pedum uri ultimi paris latus, duplo longior quam latior. Telson 

 rotundatum, latius quam longius, segmento ultimo uri multo brevius, pedunculum pedum 

 uri ultimi paris latitudine aequans, ac dimidio pedunculi ejusdem multo brevius. 



K. St. Vet. Akad. Handl. Band. 22. N:o 7. 



