AUorchestes 581 



13. Geu. AUorchestes Dana 



1849 AUorchestes (part.), J. D. Dana in. Amer. J. Sei., ser. 2 v.8 p. 136 [ 1852 A. 

 (part.), J. D- Dana in: P. Amer. Ac, v.2 p. 205 | 1888 A. (part.), T. Stebbing in: Rep. 

 Voy. Challenger, i;. 29 p. 1686 | 1880 AspidopJioreia (Sp. un.: A. diemenensis), Haswell 

 in: P. Linn. Soc. N. S. Wales, v. 5 p. 101. 



Distinguished from Hjale (p. 559) bj gnathopod 2 in (5 (Fig. 99 

 p. 583), which has the 5"^ joiat produced behind between the 4*^ and 6**^joints, 

 and from Hyalella (p. 574) by having the telson (Fig. 100 p. 583) more or 

 less divided; sometimes the palp of niaxilla 1 agrees with that of Hyale, 

 sometimes with that of Hyalella. 



5 accepted and 13 doubtful species. 

 Synopsis of accepted species: 



j Maxiila 1. palp not reaching apex of outer 

 1 plate — 2. 



I Maxilla 1, palp reaching apex of outer plate — 4. 



^ \ Gnathopod 1 in (5, finger mach longer tlian palm 1. A. novizealandiae . . p. 581 

 \ Grnathopod 1 in cj, finger matching palm — 3. 



f Telson divided to the base 2. A. compressus . . . p. 581 



I Telson not divided beyond the middle ... 3. A. malleolus . . . . p. 582 



J Apices of telson acute 4. A. plumicornis . . . p. 58ä 



\ Apices of telson truncate 5. A. humilis p. 584 



1. A. novizealandiae Dana 1852 A. n.-z. {^) -\- A. intrejnda (S), J- D. Dana 

 in: P. Amer. Ac, v.2 p.207 i 1853 & 55 A. n., J. D. Dana in: U. S. expl. Exp., v.lSn 

 p.894; t. 61 f. la— f((5), g — v($) j 1862 A. novae-zealandiae, Bäte, Cat. Amphip. Brit. 

 Mus., p. 37 t. 6 f. 3 I 1886 A. neo-zelanica, G.M.Thomson & Chilton in: Tr. N. Zealand 

 Inst., ul8 p.l44 I 1S93 Hyale jyrevostii {i)art.), A.DellaValle in: F.Fl.Neapel, u20 p. 519. 



Side-plate 4 very large. Antenna 1, flagellum more than twice as 

 long as peduncle, 16-jointed. Antenna 2 in 9 little louger than antenna 1, 

 more considerably longer in d, in c5' scarcely ^/g as long as body, flagellum 

 longer than peduncle, with 14 very slender joints. Maxillipeds, 3*^ Joint of 

 palp broad. Gnathopod 1 in c? quite small, 5*^ Joint fully as long as 6*^ 

 distally much broader, with narrow, subacute Prolongation of bind margin, 

 6*^ oblong, slightly wider at base, palm transverse, excavate, defined by an 

 acute tooth, finger more than twice as long as palm. Gnathopod 2 in cJ, 

 5*^^ Joint narrowly produced between 4*^ and 6^^, 6*^ large, ovate, palm nearly 

 straight, oblique, longer than bind margin, spinulose, finger long, yet not 

 reaching rounded end of palm. Gnathopod 1 in 9 , 5*^ Joint distally wide, 

 but without acute process, &^^ widening a little to truncate palm, finger not 

 longer than palm. Gnathopod 2 in Q , 4*^ Joint somewhat produced, 5*^ 

 strongly produced along bind margin of 6*^, process with a rounded apex, 

 6*^ as in gnathopod 1 but rather larger. Peraeopods 3 — 5 successively longer, 

 setae minute, 4*'^ Joint expanded, especially in peraeopod 3. Uropod 1, one 

 of the rami (in figure) with only apical spines. L. 10 mm. 



Pacific (New Zealand, in holes in wood bored by Teredos; Valparaiso?). 



2. A. compressus Dana 1852 A. compressa -f- -^^ australis, J. D. Dana in: 

 P. Amer. Ac, v. 2 p. 205, 206 1 1853 & 55 A. a. + A. gaimardii?, J. D. Dana in: U. S. 

 expl. Exp., V. 13ii p. 892 t. 60 f. 7a— o; p. 884 t. 60 f. la— i | 1862 A. a. + A. g., Bäte, 

 Cat. Amphip. Brit. Mus., p. 45 t. 7 f. 6; p. 41 t. 6 f. 9 | 1880 Asjndophoreia diemeiiensis, 

 Haswell in: P. Linn. Soc. N. S. Wales, v. 5 p. 101 t. 6 f . 2 | 1893 Hyale prevostii (part.) 

 + H.pontica (part.), A. Della Valle in: F. Fl. Neapel, v. 20 p. 519, 523, 528, 530. 



