296 THE VOYAGE OF H.M.S. CHALLENGER. 



He classifies the " Amfipodi genuini " in this way : — Fam. I. Gammaeidei. Subfam, L 

 Ampeliscini. Genera Ampelisca. ArrineojJS. Subfam. II. Talitrinl Genera, Orchestia, 

 Talitrus. Subfam. III. Lisianassini. Genera, Lysianassa, Gallisoma, Ichnopus, Alibrotus, 

 Phlias, Acanthonotus. Subfam. IV. Gammarini. Genera, Egidia, Melila, AmxiMihoe, 

 Amjiluthonotus, Nototropis, Epimeria, Proholium, Gammarus, C&'adocus, Elasmopus. 

 Subfam. V. Leucotoini. Genus, Leueothoe. Fam. II. Podoceridei. Subfam. VI. 

 PoDOOERiNi. Genera, Eridhonius, Cerapodina, Cerapu.% Podocerus. Subfam. VII. 

 Unciolini. Genera, Microd.eiitopus, Unciola. Subfam. VIII. Corofiini. Genus, Gcn-o- 

 phiiwi. To illustrate the incompleteness of this classification, he notices that he has 

 forthwith to add two other genera, " Pontoporcja," Kriiyer, and " Bathyporej'a," Lindstr0m. 



Of his new genus Araneops, he gives the following description : — " Caput elongato-conicum. 

 Ocelli guatuor in capitis vtiargine antico posUi. Antennx superiores unisetx; inferiores 

 longiores, pone illas insertx. Epimera quatuor anteriora infra valde producta, media 

 augustiora. Pedes primi et secundi pans subxquales, prehensiles, wigiie intus serrato ; 

 tertii et quarti cylindracei, ungue longo, articul.um antepenultimum, ultimis duobus sivml 

 valde majorem, apice attingente. Pedes quinti, seti [se«ft'] et septimi paris articulo primo 

 valde elato, laminari." He recognises its close affinity with Ampelisca, Kr0yer, of which it 

 is in fact a synonym. The type species, Araneops diadema, Tav. i. fig. 1, is set down by 

 Sp. Bate, Heller, and J. V. Carus, as a synonym of " Ampelisca Gaimardii," Krpyer, by 

 Boeck as a synonym of Ampelisca tenuicorms, Lilljeborg, 1855. Costa's second species, 

 Araneops hrevicornis, Tav. i. fig. 2, is by Carus named Ampielisca brevicornis (Marion), but 

 by Boeck made a synonym oi Ampelisca macrocepliala, LUljeborg, 1852. 



After mentioning Orchestia littorea, Costa describes his species Orchestia mediterranea, and 

 Orchestia constricta, the latter of which Heller identifies with " Orcliestia Montagui," Aud. 



Of Lysianassa, Costa describes and figures his three species, 1. Lysianassa spinicm-nis, Tav. 1, 

 fig. 4, a species not to be confused with Lysianassa (Ichnopus) spinieornis, Lilljeborg, 1865 ; 

 2. Lysianassa loricafa ; 3. Lysianassa humilis, which HeUer thinks may be the same as 

 "Lysianassa Costse," M.-Edw., which Costa mentions as being found with it. 



Oallisoma punctatum, Costa, and Gallisoma hopei, A Costa, are mentioned, but as nothing is 

 said of Gallisoma barthelemyi, Hope, it may be presumed that Costa had ceased to consider 

 it a distinct species. 



The genus lehnopjus, evidently by the derivation intended to be Ischnopus, is thus defined : — 



" Antennm longx, graciles, superiores bisetse. Pedes quatuor anteriores longi, graciles, filiformes, 

 hand prehensiles, primi unguiculo minuto infra pectinato terminati; secundi submembranacei, 

 manu apice longe fimbricda, unguicido vix consp>icuo." From Gallisoma, which it resembles 

 in the gnathopods, it dififers, he says, in the antennas, while from Alibrotus, which it 

 resembles in the antennse, it differs in the gnathopods. He adds, " 6 in questo genere die 

 abbiam trovate quelle appendici simQi alle branchie de' decapodi, inserite aU'origine de' 

 picdi toracici in forma piramidale, con uno stelo mediano, ed vma serie di lamine da cadaun 

 lato, accoUate le une aUe altre, e decrescenti dalla base all' estremiti, che rappresenta I'apice 

 della piramide." For tliis form of the branchiae, see also Grube's account, 1866, of his 

 Lysianassa longicornis ? , (which is probably Costa's L:hnopus taurus), and Boeck's remark, 

 De Sk. eg arkt. Amph. p. 323, that it is especially characteristic for many species of the genus 

 Atylus, that, like Ichnopus, their branohise have "en ophaist Rib be langs Midten, hvorfra 

 der udgaar talrige Folder som Sideribbe i et Blad." I have called attention to a similar 

 structure also in Byhlis hallarthros from Singapore. The type species of Costa's genus, 

 Ichnopus taurus, is figured Tav. i. fig. 3. 



The genus Egidia is thus defined : — 



"Antennx superiores bisetx ; inferiores artindo prrimo inerini. Pedes quatuor anteriores minuti, 

 prehensiles, siibxquales ; tertii paris articulo ultimo spatuliformi ; quarti compressi, valde 



