krammet bred og tyk Børste, hvis konvexe Kami eller Flade 

 er besat med finere eller grovere Sagtænder i parallele 

 Rader og for de ventrale en lidt svagere bøiet Børste, der 

 paa et tyndere Skatt bærer en knivfbrmig bredere Endedel, 

 der er sagtakket som de dorsale Børster, og hvis Spidse 

 er let krummet, enkelt eller todelt, stundom ret (enkeltvis, 

 Antinoi Sarsi og Melcmis Loveni, udtrukket i en lang, syl- 

 formig Spids). Hyrenes ydre Karakterer influeres at' Bør- 

 sterne alene ettersom disse ere kortere eller længere, ikke 

 at de smaa Variationer i Formen, medens dog innen af 

 Delene har Indflydelse paa Forknudernes Bygning, hvad 

 iler sees tydeligt nok hos Melcmis Loveni, der har den 

 mest afvigende Børsteform, idet de dorsale Børster ere 

 mægtige, sylformige og de ventrale dels særdeles lange og 

 tynde, dels kortere og tykkere med dybt, omtrentlig lige- 

 lint todelt Spids: trods det er Dyrets hele ydre Habitus 

 den almindelige hos de korte Polynoer. Polynoe scolopen- 

 å/rina, Enipo Kinbergi, og Nemidia Torelli, der ved sin 

 langstrakte Form og den af Skjælene ubedækkede forholds- 

 vis betydelige Del af Kroppen, saa stærkt skille sig fra de 

 korte Former, vise derimod en forholdsvis kun riuge Af- 

 vigelse i Børsteformen, en Afvigelse, der nærmest synes at 

 være afhængig af Børsternes større Spædbed i det Hide, 

 idet den væsentligst bestaar i en manglende eller kun 

 meget rin Sagtanding af de dorsale Børster. 



Lige saa lidt som jet; kan rinde, at Børsterne afgive 

 noget menet heldigt Grundlag for en naturlig Sondring af 

 Polynoerne i saa mange Slægter, ligesaa lidt rinder jeg dem 

 skikkede til at lette Diagnosen af Arterne. I denne Hen- 

 seende synes Skjællene, sjiecielt deres Ddseende under 

 Mikroskopet at frembyde større Fordele, idet tieres Bygning 

 synes at være aldeles karakteristisk for hver Art. og det 

 er nærmest støttet paa Skjællenes Bygning, at jeg maa 

 nedlægge bestemt Protest mod en saa omfattende Sammen- 

 slaaen af Arter og Slægter til en enkelt Art som den af 

 Mobius og efter ham af Tauber foretaene. 



Skulde man ville dele de nordiske Polynoer i for- 

 skjellige Grupper, saa synes den mest naturlige at vaie 

 den allerede af Ørsted foreslaaede Deling, nemlig at skjelne 

 niellem de lange og de korte Former: men det forekommer 

 mig tvivlsomt. om man er berettiget til at give dem sær- 

 skilte Slægtsnavne; thi vil man lor en naturlig Inddeling 

 tane noget Hensyn til Dyrenes indre anatomiske Bygning. 

 saa vil man vistnok hos alle disve Dyr forgjæves lede efter 

 snart sagt endog den mindste Forskjel i Bygning af Tarm- 

 kanal. Nervesystem, Kjønsorganer og Muskelanordning. Nogen 

 aldeles afgjørende Dom kan jeg ikke iidtale herom, da 

 de tre ovennævnte Repræsentanter lor de lange Former ikke 

 har staaet til min Raadighed til anatomisk Undersogelse ; 



Polynoæ, with the exception ol' Melænis Loveni and Polynoe 

 SCOlopendrina, in which it is somewhat modified, those ani- 

 mals having the dorsal bristles broad, thick, and slightly 

 arcuate, with the convex margin or surface more or less 

 minutety serrulated, the teeth being arranged in parallel 

 rows: their ventral bristles, which are also curved, though very 

 slightly, have a thinnish shaft, with a comparatively broad 

 cultrate outer portion, serrate like the dorsal bristles, the 

 point, simple or bipartite, being slightly arcuate, sometimes 

 straight (in Ant/nor Sa/rsi und Melænis Loveni produced 

 styliform). It is the relative length of the bristles, and 

 not trilling variations in form, that is found to influence 

 the external characters of the animals; but neither of these 

 subordinate features has the slightest influence on the struc- 

 ture of the pedal protuberances, a fact distinctly appa- 

 rent on examining Melænis Loveni, in which the bristles are 

 most aberrant in form, those on the dorsal surface consis- 

 ting of powerful, styliform spikes, while those on the ventral 

 are in part exceedingly long and thin, and in part com- 

 paratively short and thick, with deeply cleft bipartite 

 points: and yet the habitus of the animal does not differ 

 from that distinguishing the other short Polynoæ. Even 

 Polynoe scolopendrina, Enipo Kinbergi, and Nemidia Torelli, 

 so easily distinguished from the short forms by reason of 

 their elongate structure and the portion of the body, com- 

 paratively considerable, that is scaleless, exhibit but very 

 slight variation in the bristles, a variation chiefly dependent, 

 it would seem, on greater delicacy of structure, the serra- 

 ted margin, for instance, distinguishing in other Polynoæ 

 the dorsal bristles, being altogether absent, or with the 

 teeth exceedingly minute. 



And this, as I conceive, peculiar unfitness of the 

 bristles to furnish a sure and obvious basis on which 

 might be established a natural division of the PolynoidcB into 

 numerous genera, extends. I think, with equal force to specific 

 diagnoses. The scales, more especially their appearance 

 under the microscope, afford, in my opinion, far greater 

 distinctive facilities, their form and structure being, it seems, 

 in each species characteristically constant; and it is indeed 

 on grounds derived from a close examination of the scales, 

 that I venture emphatically to oppose the wholesale hea- 

 ping together by Mobius. and after him by Tauber, of 

 proposed genera and species into a single specific group. 



Assuming the need of further classification for the 

 northern Polynoæ. the most natural would surely be to 

 distinguish, as suggested by Ørsted, between the long and 

 the short forms. Meanwhile. I very much question whether 

 such groups be entitled to generic rank: for if. in that 

 case, any weight must be laid on anatomical structure, it 

 would certainly be hard to rind in any of these animals 

 the slightest difference in the stucture of the intestinal 

 canal, the nervous system, the generative organs, or the 

 muscular arrangement. A decided opinion on this sub- 

 ject. I cannot, however, venture to pronounce, my ana- 

 tomical investigations having been exclusively confined to 

 representatives of the short forms; but after carefully 



1* 



