Tetradeion, Cyproidea 157 



5. Gen. Tetradeion Stebb. 



1899 Tetradeion (Sp. typ.: Cyproidia crassa) (non Tetradium J.D.Dana 184*), 

 ■Onidaria), T. Stebbing in: Ann. nat. Hist., ser. 7 «;. 4 p. 207. 



Body Short and stout. pleon shorter thau peraeon. Head small, rostrum 

 obsolete. Side-plates 1 — 4 together forming a continuous shield, the confronted 

 margins of the contigiious side-phites neatly fitting, 4^^ rauch broader than 

 V^ to 3^ combined, 5*^ rauch broader than deep, titting hind emnrgiuation 

 of 4*^ 6*^ and 7**^ concealed. Eyes well developed. Antennae 1 and 2 small. 

 Anteuna 1 the stouter, without accessory flagellura. Antenna 2, penultimate Joint 

 of peduDcle shorter than antepenultimate. Mouth-parts unknown. Gnathopods 1 

 and 2 equal, similar, imperfectly subchelate, 4*^^ and 5*^ joints slightly produced. 

 Peraeopods 1 — 5 slender, character of 2^^ Joint unknown, but expansion 

 rendered needless by the gTeat extent of side-plate 4. üropod 1, rarai shorter 

 than peduncle, subequal. Uropod 2 reaching as far back as uropod 1, rami 

 ii little unequal. üropod 3 not reaching so far back as tlie other pairs, 

 stouter, rarai decidedly unequal. Telson entire, oval, short. 



1 species. 



1. T. crassum (Chilton) 1883 Cyproidia? crassa, Chilton in: Tr. N. Zealund 

 Inst., 1.15 p. 80 t.3 f . 1 j 1899 C. c, Tetradeion sp. typ., T. Stebbing- in: Ann. nat. Hist., 

 ser. 7 i;. 4 p. 207. 



Side-plate 1 broader thau 2*^ or 3**, but not so deep, 4*^ deeper than 

 the rest, rauch broader than deep. Pleon segment 3, postero-lateral angles 

 not produced. Eyes large. Antenna 1. P* and 2*^ joints stout, subequal, 

 2*^ produced into a tooth over the sraall stout 3<^, flagellura 6- or 7-jointed, 

 tapering, with long sensory filaments. Anteuna 2, antepenultimate Joint 

 rauch longer, ultimate rather longer than penultiraate Joint of peduncle, flagellura 

 subequal ultiraate Joint of peduncle, with 4 joints, 1®* the longest. Gnatho- 

 pods 1 and 2, ö^^ Joint bluntly produced, 6*^^ rather narrow, slightly tapering, 

 scarcely forming a palra for the sraall finger. Peraeopods 1 — 5 subequal, finger 

 small. Uropods 1 and 2, the louger ramus with 2 spiuules. üropod 3, rarai 

 unarraed, one shorter, the other longer than the peduncle. Telson apically 

 a little narrower than at base. Colour browu. L. about 3*5 ram. 



Lytteltnn Harbour [New Zealand]. 



6. Gen. Cyproidea Hasw. 



1880 Cyproidea, Haswell in: Ann. nat. Hist., ser. 5 v.b p. 31 | 1880 Cyproidia 

 (part.), Haswell in: P. Linn. Soc. N.8. Wales, i;. 4 p. 320 | 1885 C. (part.), T. Stebbing 

 in: Ann. nat. Hist., ser. 5 u 15 p. 59 | 1888 C, Peltocoxa?, T. Stebbing in: Rep. Voy. 

 Challenger, v.29 p. 513 | 1893 P. (part.), A. Della Valle in: -F. Fl. Neapel, t. 20 p. 647 

 1881 Cypridoidea., E. C. Rye in: Zool. Reo., v. 16 Index p. 4. 



Body Short and stout. Side-plates 1 and 2 rudimentary, 3*^ and 4*^ very 

 large, confronted raargins closely fitting, 6*^ and 7*^ concealed. Eyes well 

 developed. Antennae 1 and 2 sraall. Antenna 1, peduncle rather stout, accessory 

 flagellura wanting. Antenna 2 slender. Epistome strongly projecting. Upper 

 lip unsyrametrically bilobed. Lower lip apparently with inner lobes obsolete. 

 Mandible, cutting edge with numerous teeth, accessory plate on left raandible 

 also dentate, spine-row well developed, molar wanting, palp slender, 3-jointed, 

 1^*^ Joint not very short. Maxilla 1, inner plate with 1 spinule on rounded 

 apex, outer with 7 or 8 spines, palp large, 1-jointed. Maxilla 2, inner plate 



