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



but still there are more particulars worth mentioning which, I hope, will settle the question 

 about the right and due name of this species. 



That the specific name y>medusarum* 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, 0. Fabkicius,» may be another species than ^Cancer medusarum, 0. F. Muller», 

 the species of 0. Fabricius cannot be identical with Hyperoche Kroeyeri. Fabri- 

 cius says: 1 ) 



»Pedes 14, quorum 8 antici antrorsum, 6 postici retrorsum tendunt; sunt 10 postici 

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

 curuo); 4 antici pro manibus habendi, breuiores, biarticulati, articulo secundo etiam com- 

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

 vPedes . . . 10 postici similes* opposes decidedly the characteristic of Hyperoche Kroeyeri, 

 *Pedes triam p avium ultimorum pedihus tertii ac quarti parium multo longioves*, and re- 

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

 . . . margine inferiore bis inciso*, may be pointed out that *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 certainly have attracted 

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

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



Kroeyer in 1838 gives no reason why his species and Oniscus medxisavum, 0. 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 

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

 nym for it, and suggests that Talitus cyaneae, 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 

 exerciser However, I am not perfectly sure that the animal he studied was a Hyperoche 

 Kroeyeri, possibly it was a Hyperia medusarum, 0. F. Muller, or a H. Latreillei, H. 

 Milne Edwards. A. White in 1857 1. c. p. 207 cites Metoecus medusarum, 0. 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, 0. 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. Goes in 1865 quotes Hyperia medu- 



l ) 0. Fabricius, Fauna Groenlandica, p. 257. Copenhagen and Leipsic 1780. 



1 2 



K. Sv. Vet. Akad. Handl. Band. 22. N:o 7. L * 



