KONGL. SV. VET. AKAUEM1ENS HANDLINGAR. BAND. 22. N:0 7. 253 



The reasons why I here take Parathemisto abyssorum, A. Boeck, as a synonym for 

 Hyperia oblivia, H. Kroeyer, are that the few characteristics given by Kroeyer exactly 

 agree with those of Parathemisto abyssorum, and that Boeck never Avas aware of the fact 

 that Hyperia oblivia belonged to the new genus Parathemisto, and so in 1872 he gave Hyjjeria 

 oblivia as a synonym for H. medusarum and thus did nothing to clear up the question. 



The diagnosis of the species given by Kroeyer in 1838 runs: 



» Hyperia oblivia: antennis superioribus brevioribus, validis, uncinatis, setosis; antennis in- 

 ferioribus gracilibus, flagello scapum longitudine ter superante; pedibus secundi paris gracilibus, 

 margine tertii et qvarti articuli posteriore infra in stylum producto, ungue non inflexo; pedibus 

 tertii qvartique paris, ut duo paria priora longitudine superantibus, ita a paribus seqventibus, 

 qvse invicem ejusdem fere sunt longitudinis, superatis. Qvinqve paria ultima formara horuin 

 pariuin in Metoeco Medusarum prorsus imitantur.w 



From his description I translate the passages respecting the first two pairs of perseo- 

 poda, the rest of the description being of but little importance for the identification of 

 the species. 



»The first pair of legs are small but robust: the first joint is the longest and is tolerably 

 thick; the second and third joints are very short, and so closely united, that it is difficult to see the 

 line of junction between them; the fourth joint is longer than the two preceding together, and is very 

 thick; the fifth joint is about as long as the fourth, somewhat more slender, and a little narrowed 

 at the apex; the sixth joint is a tolerably long and acute claw, which is not much curved. Some 

 long, -very slender and soft hairs are to be seen at the hind corner of the under margins of the 

 first three joints, along the hind margin of the fourth joint, and on both the front and hind 

 margins of the fifth joint. 



The second pair of legs are longer than the first, but are more slender; the relation of 

 length between the different joints is almost the same, but the third and fourth are produced 

 downwards from the apex of the hind margin into a tolerably long process. The claw is very 

 slender, and not curved; the covering of hairs is less rich than in the preceding pair.» 



H. Milne Edwards in 1840 gave the following short description probably taken 

 principally from the drawing of Kroeyer: 



»Antennes inferieures plus longues que les superieures; leur dernier article tres-allonge et 

 tres-grele. Pates de la troisieme et de la quatrieme paire allongees. Lame terminale de l'abdo- 

 men triangulaire et pointue au bout. Article basilaire des dernieres fausses pates tres-etroit et 

 allonge. » 



A. Boeck in 1870 instituted the new species Parathemisto abyssorum with the follow- 

 ing diagnosis, which he repeated in 1872: 



»Carina spinas retroversas non formans. Pedes 3tii et 4ti paris articulo 4to subangusto. 

 Pedes 5ti paris articulo 3tio parum modo breviore qvam 4to. l ) 



From his very incomplete description of 1872 I translate what he says about the 

 first and second pairs of pera;opoda for a comparison with Kroeyer's description: 



»The carpus of the first pair of legs is broad, provided on the hind margin with stout 

 bristles, and is not produced into a heel; the hand (= metacarpus) is about as long as the carpus 



*) This last statement is evidently an error as it is quite contrary to what he himself delineates on plate 

 3. fig. 1 n, and to what 1 have seen in his own type specimen, which lies before me. 



