I. Leg. Gammaridea 



1852 Subtrib. Gammaridea, J. D. Dana iu: Amer. J. Sei., ser. 2 «'.14 p. 308 | 

 1853 Subtrib. G., 3. D. Dana in: U. S. expl. Exp., u 13ii p. 806. 825 \ 1861 Trib. 

 Prostomatae -{- Gammaridae, A. Boeck in: Forh. Skand. Naturf., Made 8 p. 637, 639 | 

 1888 Trib. AmpMpoda Gammarina, T. Stebbing in: ßep. Voy. Challenger, t\29 p. 601 | 

 1890 Trib. Gammaridea, G. 0. Sars, Crust. Norvvay, v.l p. 21 | 1893 Subord. Gammarini, 

 A.DellaValle in: F. FI. Neapel, w. 20 p. 297. 



Head not fused with 1 ^* peraeon segment. Eyes usually Compound, 

 even wlien externally simple, but sometimes reduced to mere pigment patches 

 Ol" entirely absent; normal number 2, varying to 1, 3, 4 or 6 (p. 104): the 

 Cornea of each eye sometimes forming a lens*). Antenna 1 consisting of 3-jointed 

 peduncle and flagellum, with or without accessory flagellum. Antenna 

 2 longer or shorter than antenna 1 or equal to it; peduncle apparently 

 5-jointed, usually with conical process (gland-cone) opening on 2"^ Joint. 

 The joints of one or both antennae in d", or in d and 9, sometimes carrying 

 membranaceous appendages (calceoii, Fig. 82 p. 347). Epistomeflator projecting. 

 Upper lip with distal raargin of outer plate smooth or variously bilobed 

 (Fig. 41 p. 163). Lower lip divided into 2 principal lobes, prolonged backward 

 into the so-called mandibular processes, and often having between them 2 

 smaller inner lobes (Fig. 71 p. 278, Fig. 102 p. 598). Maudible (Fig. 77 

 p. 333) normally composed of basal Joint and 3-jointed palp; the basal Joint 

 produced to a dentate cutting edge with adjacent accessory plate on inner 

 side and armed with a spine-row between the cutting-plates and the molar, 

 which is a prominent denticulate tubercle; each one of the features some- 

 times degraded or absent (Fig. 2 p. 12, Fig. 21 p.96). Maxilla 1, 1^* and 3*1 joints 

 with expansion (inner and outer plate), surmounted by spines. which are usually 

 furcate or serrate; 4*^ and 5*^ joints forming the so-called palp (Fig. 78 p. 333, 

 Fig. 87 p. 476); the parts, especially inner plate and palp. liable to evanesceuce. 

 Maxilla 2, 1^* and 3*^ joints with expansion (inner and outer plate); the 

 plates very variable iu relative size, rarely wanting, usually in part 

 fringed with setae or slender spines (Fig. 88 p. 476). Maxillipeds (Fig. 49 

 p. 186, Fig. 54 p. 208), 2'^ and 3^ joints usually with expansion (inner 

 and outer plate); palp 2 — 4-jointed. Peraeon of 7 distinct Segments, rarely 

 reduced to 6 by coalescence of the last two. Legs of the peraeon overlapped 

 at base by the side-plates, developed from or soldered to the 1^* joints 

 of the legs; the first 4 side-plates usually larger than the 3 following, the 

 4*^ commonly the largest, but with many exceptions. Gnathopods 1 and 2 have 

 the 4*^ Joint not end to end with the b^^, but more or less underpropping it, 

 and the 6*^ Joint generally more or less expanded to form the so-called band. 

 The branchial vesicles, usually attached to o-nathopod 2 and peraeopods 1 — 4 

 or 1 — 5, are simple, twisted, pleated or divided into leaf-like lobes; simple 

 accessory vesicles rare. In the Q peraeon segments 2 — 5 are furnished at the 



*) Articulated eye-lobes without visual elements attributed to Ingolfiella Hansen 

 1903 (see p. 726). 



