GAMMARIDEAN AMPHIPODA 95 



lodes have the posterior lobe of article 5 of gnathopod 2 curved distal- 

 wards, elongated, and guarding article 6, although this condition is 

 poorly developed in M. latlssimanus, M. 7nertensi Gurjanova (1951) 

 and M. glyconka J. L. Barnard (19G2d). The first antenna is scare- 

 ly shorter than the second, the peduncle of the first antenna projects 

 at least halfway along article 4 of antenna 2, and article 3 of antenna 

 1 is less than half (usually one third) as long as article 1. Mono- 

 culopsis Sars differs from Monoculodes by the extension of antenna 1 

 beyond antenna 2 and the elongated article 3, which is as long as 

 article 1. 



Oedlceroides includes species having a very short antenna 1, which 

 rarely extends as far as the end of the peduncle of antenna 2 and often 

 only to the end of article 4 of antenna 2, the peduncle apparently never 

 extending more than halfway along article 4 of antenna 2. In con- 

 trast, antenna 2 is relatively much larger, longer, and stouter than in 

 Monoculodes and often is characterized by article 4 being stouter and 

 longer than article 5. The posterior lobes of the fifth articles of 

 gnathopod 2 are very short, often stand erect and do not guard article 

 6, although exceptions occur. The rostra of Oediceroldes are elon- 

 gated, as in Monoculodes^ but often are of more bizarre shape, although 

 O. cystifem and O. hrevlrostris, both of Schellenberg (1931), have 

 shortened rostra. Indeed, the generic position of the latter two species 

 should be reconsidered carefully because the former has an accessory 

 eye and both have very slender antennae with little resemblance to 

 other species of Oediceroldes. Their antennae and rostra do resem- 

 ble those of some of the deep-sea species. 



Oedlceroides and Monoculodes have strongly projecting and 

 toothed mandibular cutting edges, large, blunt triturative molars and 

 very long, strongly setose mandibular palps. 



The type-species of Aceroides differs from Oediceroldes and Mon- 

 oculodes in the weakly projecting and poorly toothed primary mandib- 

 ular cutting edge, and the relatively weaker palps, either thinner, 

 slightly shorter or less setose than those of Oediceroldes and Monocu- 

 lodes. The rostrmn of Aceroides extends scarcely one third along 

 article 1 of antenna 1. A long posterior lobe is present on article 5 

 of gnathopod 2 but it does not completely guard article G. Further- 

 more, coxae 3 and 4 are excavated ventrally and pereopods 1 and 2 

 are strongly modified : article 4 is widely expanded, has a strong mid- 

 lateral row of setae, has article 5 shortened, inflated, posteriorly ex- 

 tended or lobate, and article 7 is a large, flat saber. This condition of 

 coxae and pereopods 1 and 2 is typical of Oediceroldes {Patoldes) 

 synparisj although the dactyls of that species are piOorly saber shaped 



