ved en Sammenligning med Dohrn' s Værk strax falde i 

 l linene, at denne Pauna's Character er meget væsentlig 

 forskjellig fra den i Middelhavet raadende. Navnlig ei- 

 den store Artsrigdom inden Nymphonulernes Familie i hoi 

 Grad characteristisk for de nordlige Have i Modsætning til 

 Middelhavet, hvor hidtil kun en eneste herhen horende Art 

 er bleven observeret. Ogsaa er de i de nordlige Have 

 forekommende Former idethele af betydelig større (tildels 

 colossale) Dimensioner end de i Middelhavet forefundne, 

 som i Sammenligning med hine er gjennemgaaende rene 

 Dværgformer. 



Ved den systematiske Inddeling af de nordiske Pyc- 

 nogonider har jeg tildels fundet at burde tåge Familierne 

 i en noget snævrere Begrændsning end af tidligere For- 

 skere sædvanlig gjort, hvorved selvfølgelig Familiernes An- 

 tal er bleven noget forøget. Enkelte tidligere opstillede 

 Slægter, som af senere Forskere igjen er inddragne, har 

 jeg ligeledes fundet paany at maatte hævde, ligesom en 

 Del nye Slægter er opstillede. Jeg anser det for meget 

 sandsynligt, at man ved et fuldstændigere Kjendskab til de 

 existerende Arter vil finde det nodvendigt at gaa endnu 

 videre i denne Retning, og at ogsaa en høiere Inddeling af 

 Familierne i Ordener engang vil blive etableret, hvad der 

 dog for Tiden vanskeligt lader sig gjennemfore. 



Angaaende Terminologien, saa hersker her, som ogsaa 

 inden andre Grupper af Arthropoderne, stor Uoverensstem- 

 melse mellem forskjellige Autores. Kroyer, der i Lighed 

 med Mihie-Edwards var mest tilbøielig til at henregne 

 Pycnogoniderne til Crustaceerne, benytter saaledes Termini 

 hentede fra disse sidste Dyr (Mandibler, Maxiller, Rostrum), 

 medens andre Forskere, der holdt paa Pj r cnogonidernes Af- 

 finitet med Arachniderne, anvender paa de samme Dele ganske 

 andre Betegnelser, mere i Overensstemmelse med den for sidst- 

 nævnte Classe sædvanlig brugelige Terminologi. Navnlig vil 

 man finde. at de forreste Par Lemmer figurerer hos de for- 

 skjellige Autores under de mest forskjelligartede Betegnelser 

 (Mandibler, Antenner, Kindbakkeantenner, Pedipalpi, Kjæ- 

 vefodder etc). Af de nyere Forfattere har Hoel: i alt væ- 

 sentligt henholdt sig til den tidligere mest brugelige Ter- 

 minologi, medens Dohrn har for Lemmernes Vedkommende 

 opgivet enhver særskilt Betegnelse, idet han blot beskriver 

 dem efter deres Orden som No. I, II, III etc. Dette er 

 vistnok en meget nem Maade at undgaa alle Vanskelighe- 

 der, men Methoden er neppe praktisk og vil derfor vistnok 

 ikke blive adopteret af andre Forskere. En Terminologi 

 faar man nok bekvemme sig til at anvende; men jeg tror, 

 at man her gjør rigtigst i at vælge saavidt muligt indiffe- 

 rente Betegnelser, der ikke involverer nogen Homologise- 

 ring med Lemmerne har andre Arthropoder. Nedenfor 

 meddeles de af mig i nærværende Arbeide benyttede Ter- 

 mini, hvis nærmere Forklaring vil sees af hosstaaende 

 Figur, forestillende en Nymphon-Art seet fra Rygsiden. 

 med kun en af Fodderne tegnet. 



to be essentially different from that of the Mediterranean 

 forms. In particular, the great number of species belong- 

 ing to the family Nymphonidæ is eminently eharacteristic 

 of the Northern Seas as contrasted with the Mediterranean, 

 where hut a single species referrable to that family has 

 been observed. Moreover, the forms inhabiting the Northern 

 Seas attain as a rule much larger dimensions (some are 

 even gigantic) than those occurring in the Mediterranean, 

 which, compared to the former, must be regarded as 

 veritable dwarf-forms. 



In working out the systematic classification of the 

 Northern Pycnogonidea, the author has partly found reason 

 to take the families in a somewhat more restricted sense 

 than generally done by earlier naturalists, thus occasioning 

 a slight augmentation in the number of families. A few 

 formerly established genera, rejected by subsequent zoolo- 

 gists, he has also seen tit to maintain, and some new 

 genera have likewise been instituted. I regard as highly 

 probable, that a more intimate acquaintance with the 

 existing species will of necessity lead still farther in the 

 same direction, and also that a higher division of the 

 families into orders must eventually be made, though at the 

 time being such an innovation would most certainly prove 

 difficult to carry out. 



As regards the terminology, very considerable dis- 

 agreement is found to prevail, alike in this group and in 

 other divisions of the Arthropoda. Kroyer, who, in com- 

 mon with Milne-Edivards, felt most inclined to class the 

 Pycnogonids with the Crustaceans, adopts terms tåken from 

 the latter animals (mandibles, maxillæ. rostrum], whilst 

 other authors, that held to the affinity of the Pycnogonidea 

 with the Arachnida, apply for the same parts totally dif- 

 ferent appellations, more in accordance with the termino- 

 logy in general use for the latter class. In particular, 

 it will be found that the foremost pair of limbs figure 

 among the various authors under the most heterogeneous 

 designations «(mandibles, antennæ, maxillary palps, pedipalpi, 

 maxillary feet, etc). Of later authors, Hoek has kept in 

 all essentials to the terminology most in use formerly, 

 whereas Dohrn, as regards the limbs, has rejected every 

 separate appellation, simply describing them in their natural 

 order, as No. I, II, III, etc This is certainly a very 

 convenient way of getting over difficulties, but the method 

 can hardly be termed practical, and therefore stands little 

 chance of being adopted by other authors. A terminology 

 of some lund we must submit to use; but in my judgment 

 we should as far as possible make choice of indifferent 

 terms that do not involve anything homologous with the 

 limbs in other Arthropoda. Overleaf are given the terms 

 employed in the present Meinoir, the more precise signi- 

 fication of which will be seen from the accompanying figure. 

 that represents a species of Nymphon, — dorsal aspect, — 

 with only one of the legs fully drawn. 



