Amphipoda 



1775 Gen. Ganimarus (part.) -j- Gen, Oniscus (part.), J. C. Fabricius, Syst. Ent., 

 p. 418, 296 i 1793 Subgen. Gammarellus (part.), J. F. W. Herbst, Naturg. Krabben 

 Krebse, v. 2 p. 106 | 1802 Fam. Gammarinae (ex ürd. Branchiogastra), Latreille, Hist. 

 Crust. Ins., V.3 p.38 | 1813/14 Trib. Gasteruri (part.), Leacb in: Edinb. Enc, r.7 p.386 | 



1815 Leg. JEdriophthalma (part.), Leach in: Tr. Linn. Soc. London, u 11 p. 307, 352 j 



1816 & 17 Ord. Amphipoda, Latreille in: Nouv. Dict., ed. 2 v.l p.467; ».8 p.493 i 1888 

 Subord. A., T. Stebbing in: Rep. Voy. Challenger, v. 29 p. 601 | 1890 4., G. 0.' Sars, 

 Crust. Xorway, v. 1 p. 3. 



Head carrying 2 pairs of antennae, the mandibles, 2 pairs 

 of maxillae, and the basally coalesced maxillipeds. Cornea of 

 eyes not divided into facets. Peraeou consisting usually of 7 Seg- 

 ments, each bearing a pair of legs; first segmeut sometimes fused 

 with head. Pleon consisting normally of 6 segments and the telson, 

 Ol' rudimentary; if normal, bearing 6 pairs of legs, the first three 

 of which, functioning as swimming organs, differ in structure 

 from the rest. Organs of respiration (branchial vesicles) attached 

 to the peraeon, not to the pleon. Heart (in a pericardiac sinus) 

 never exceeding hinder limit of peraeon, with aorta also at posterior 

 extremity. Antennal gland preseut, though sometimes small. 



The body, often compressed, sometimes depressed, or piriform, or even 

 rodlike, consists ofhead, peraeon and pleon. The number of its fi*ee 

 Segments reaches 15 (head 1, peraeon 7, pleon 7). First segment of peraeon 

 sometimes coalesced with head, rarely with 2^ segment of peraeon; fusion 

 of the last 2 segments of peraeon occurs. Pleon often as long as peraeon, 

 or even rather longer; the limits between the hinder segments occasionally 

 disappear; in the Caprellidea the pleon is rudimentary. The last pleon segment 

 is the telson. 



Appendages of head: 1) First antenna; peduncle of 3 (rarely 

 fewer) joints, with a many-jointed primary fiagellum and usually a shorter 

 accessory flagellum. 2) Second antenna; peduncle of 5 joints, with one 

 flagellum; the first 2 joints of peduncle are short and not always distinct; 

 the 2*^ usually with a conical process (gland-cone) for the opening of the 

 antennal gland. The length of antenna 1 and 2, in proportion to each other 

 and to the body varies within wide limits. 3) Mandible (Fig. 7, 8 p. 30, 32); 

 basal Joint provided with masticatory structures; palp with 3 or fewer joints, 

 or absent. Between the mandibles the upper lip, attached to the epistome, 

 and the lower lip frame the entrance to the Oesophagus. 4) First 

 maxilla (Fig. 78 p. 333) consisting of 5 joints; the palp, that is the 4*^^ 

 and 5*^ joints, not rarely wanting. 5) Second maxilla (Fig. 88 p. 476) 

 consisting of 3 joints. In maxilla 1 and maxilla 2 the 2*^ Joint is indistinct, 



Das Tierreich. 21. Lief. : T. E. R. Stebbing, Amphipoda I. 1 



