KONGL. SV. VET.- AKADEMIENS HANDLINGAR. BAND. 22. N:0 7. 89 



biit still there ave moi-e particulavs worth nientioniiig wjiich, I liope, will settle the questioii 

 about the riglit and due name of this species. 



That the specific name miedusarum-» by no means can be applied on this species I 

 have showed above, p. 84; here I shall spend some words to prove that, if also »Oniscus 

 medusarum, O. Fabuicius,» may be another species than nCancer medusarum, O. F. Mulleii», 

 the species of O. Fabricius cannot be identical with Hyperoche Kroeyeri. Fabri- 

 cius says:') • 



»Pedes 14, qnorum 8 antici antrorsuin, 6 postici retrorsum tendunt; sunt 10 ijostici 

 ceterum similes 3-articulati (femore corapresso, tibia tereti tenuiore, apice acuto longiori 

 ciiruo); 4 antici pro manibus habendi, breuiores, biarticulati, articulo secundo etiam coni- 

 presso, margine inferiore bis inciso et ungue terminali mobili.» Against the characteristic 

 yiPedes . . . 10 postici similes''^ opposes decidedly the characteristic of Hyperoche Kroeyeri, 

 ))Pedes trium parium ultimorum pedibus tertii ac quarti parium multo longiores>\ and re- 

 garding the characteristic quoted by Fabricius (pedes) »4 antici pro manibus habendi . . . 

 . . . margine inferiore bis incisoi\ may be pointed out that y)bis inciso^ probably means the 

 tibial and carpal processes such as they are to be seen in Hyperia galba, Montagu, or 

 H. Latreillei, H. Milne Edwards, and not the perfect cheliform hand so distinctly developed 

 in a Hyperoche. Such a typical prehensile organ would cei^tainly have attracted 

 attention of such an acute observer as Fabricius, who at the next preceding page of 

 »Fauna Groenlandica» mentions the hand of Gammarus (Oniscus) pulex. 



Kroeyeh in 1838 gives no reason why his species and Oniscus medusarum, O. Fa- 

 bricius, should be the same; he only says 1. c. p. 63, »That the present species {Metoecus 

 medusarum) is identical with Fabricius' Oniscus Medusarum, seems to be beyond doubt». 



H. Milne Edwards in 1840 1. c. p. 78 quoting Metoecus medusarum, with the 

 sjmonymy given by Kroeyer, adds that the »marflue» of Str0M probably also is a syno- 

 nym for it, and suggests that Talitus cyanece^ Sabine, very likely comes near to Metoecus; 

 for the synonymy of this latter species, see below under Hyperia medusarum, O. F. 

 Muller. Ph. Gosse in 1853, 1. c. p. 367, mentions Metoecus medusarum., Kroeyer, and 

 gives some biological notices about it, so he says: »There (in a Chrysaora) he snugly 

 ensconses himself, and feels so much at home, that he is not afraid to leave his dwelling 

 now and then, to take a swim in the free water, returning to his chamber after his 

 exercise». However, I am not perfectly sure that the animal he studied was a Hyperoche 

 Kroeyeri, possibly it was a Hyperia medusarum, O. F. Muller, or a H. Latreillei, H. 

 Milne Edwards. A. White in 1857 1. c. p. 207 cites Metoecus medusarum., O. Fabri- 

 cius; this animal is not unlikely the true species of Kroeyer, according to the charac- 

 teristic quoted, »Five last pairs of legs very slender, the three last longer than the others». 



Spence Bate in 1862 in his »Catalogue», p. 293, records Metoechus medusarum^ 

 A. White, as a synonym for Hyperia galba, Montagu, and again, 1. c, p. 295, M. medu- 

 sarum, Kroeyer, as a synonym for H. medusarum, O. Fabricius, in fact Kroeyer's species 

 has nothing to do with neither of the two cited species, as is easily seen from the de- 

 scriptions and drawings given by Spence Bate. A. GoÉs in 1865 quotes Hyperia medu- 



') O. Eabricius, Fauna Groenlandica, p. 257. Cope.nliag:en and Leipsic 1780. 



1 9 



K. Sv. Vet. Akad. Handl. Baud. 22. N:o 7. ■*■ ^ 



