ki'Limiiiet bred og tvk Borste, livis kuiivexe Rand ellev Flade 

 er besat med tiuere eller srovere Sagtieuder i parallele 

 Rader og for de veutrale en lidt svagere boiet Børste, der 

 paa et tyndere Skaft banker en kuivforniig bredere Endedel. 

 der er sagtakket som de dorsale Borster. og bvis 8pidse 

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

 Aiit/iioe Sarsi og Mclæiiis Loreiil, udtrukket i en laug. syl- 

 formig Spids). Dyrenes ydre Karakterer influeres af Bør- 

 sterne alene eftersom 'disse ere kortere eller længere. ikke 

 af de' smaa Yariationer i Formen, medens dog ingen af 

 Delene bar Indflydelse paa Forkniiderues Bygning, bvad 

 der sees tydeligt nok bos Melænis Loceni. der bar den 

 mest afvigende Borsteform. idet de dorsale Børster ere 

 mægtige. sylformige og de ventrnle dels særdeles laiige og 

 tynde. dels kortere og tykkere nu'd dybt. omtrentlig lige- 

 ligt todelt Spids; trods det er Dyrets bele ydre Habitus 

 den almindelige bos de korte Polynoer. Polynoe scolopen- 

 drina, Enqw Khihercji, og Nemidia Tor ell K der ved sin 

 langstrakte Form og den af Skjælene ubedækkede forbolds- 

 vis betydelige Del af Kroppen, sa a stærkt skille sig fra de 

 korte Former, vise derimod en forboldsvis kun ringe Af- 

 vigelse i Børsteformen. en Afvigelse. der nærmest synes at 

 være afbængig af Børsternes større Spædbed i det Hele. 

 idet den væsentligst bestaar i en manglende eller kun 

 meaet fin Sastanding af de dorsale Borster. 



Lige saa lidt som jeg kan tinde, at Børsterne afgive 

 noget meget beldigt Grundlag for en naturlig Sondring af 

 Pohjnoerne i saa mange Slægter. lisesaa lidt tinder jeg dem 

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

 seende synes Skjællene. specielt deres Udseende under 

 Mikroskopet at frembyde større Fordele, idet deres Bygning 

 synes at- være aldeles karakteristisk for bver Art. og det 

 er nærmest støttet p.aa Skjællenes Bygning, af jeg maa 

 nedlægge bestemt Protest mod en saa omfattende Sammen- 

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

 Møbius og efter bam af Taube» foretagne. 



Skulde man ville dele de nordiske Polynoer i for- 

 skjellige Grrupper. saa synes den mest naturlige at v.ære 

 den allerede af Ørsted foreslaaede Deling, nemlig at skjelne 

 mellem de lange og de korte Former ; men det forekommer 

 mig tvivlsomt. 'om man er lierettiget til at give dem san'- 

 skilte Slægtsnavne; tbi vil man for en naturlig Inddeling 

 tåge noget Hensyn til Dyrenes indre anatomiske Bygning, 

 saa vil man vistnok bos alle disse Dyr forgjæves lede efter 

 snart sagt endog den mindste Forskjel i Bygning af Tarm- 

 kanal. Nervesystem, Kjønsorganer og Muskelanordning. Kogen 

 aldeles afgjoreude Dom kan jeg ikke udtale berøm, da 

 de tre ovennævnte Repræsentanter for de lange Former ikke 

 har staaet til min Raadigbed til anatomisk Undersøgelse ; 



Polynoæ, witb tbe exception of Melænis Lorenl and- Polynoe 

 scolopeiidrina, in wbicb it is somewhat modified, those ani- 

 mals having the dorsal bristles broad, tliick. 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 conijjaratively broad 

 cultrate outer portion, serrate like the dorsal bristles, the 

 point, simph' or bipartite, being slightly arcuate, sometimes 

 straight (in Anfinoe Sarsi und Melænis Lore)ii ])roduced 

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

 not trifling variations in form, that is found to influence 

 the extei-nal characters of tbe animals; but m'ither of these 

 subordinate features has the slightest influence on the struc- 

 ture of tbe jiedal ])rotuberances. a fact distinctly ajjpa- 

 rent on examining Melænis Loveni. in which the bristles are 

 most aberrant in form, those on tbe 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 ditt'er 

 from that distinguishing the other short Polynoæ. Even 

 Polynoe seohpendrina. Enipo Kinberyi. and Nemidia Torelli, 

 so easily distinguished Irom the short forms by reason of 

 their elongate structure and tbe jjortion of tbe body, com- 

 paratively considerable, that is scaleless. exhibit but very 

 slight variation in tbe bristles, a variation chiefly dependent, 

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

 ted margin, for instance, distinguishing in other Polynoce 

 the dorsal bristles, being altogethei- absent, or with the 

 teeth e-xceedingly minute. 



And this, as I conceive, jieculiar unfitness of tbe 

 bristles to furnish a sure and obvious ■ basis on which 

 might be established a natural division of the Polynoidæ into 

 numerous genera, extends. I think, with equal force tospecitic 

 diagnoses. The scales, more especially their appearance 

 under the microscope, aftord. 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 examiniation of the scales, 

 that I venture emphatically to ojjpose tbe wholesale hea- 

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

 proposed genera and species into a single sjiecitic group. 



Assuming the need of further classification lor tbe 

 northern Polynoæ. the most natural would surely he to 

 distinguish, as suggested by Ørsted, between the long and 

 tbe short forms. Meanwhile. I very much question whether 

 such groups be entitled to generic rank : foi' if in that 

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

 would certainly be hard to find in any of these animals 

 the slightest dift'erence in tbe stucture of the intestinal 

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

 muscular arrangement. A decided opinion on this sub- 

 ject. I cannot, however, venture to i)ronounce, my ana- 

 tomical investigations having been exclusively confined to 

 representatives of the shoi-t fin-ms; but after carefully 



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