157 



EN NY ART 



AF 



SLÆGTEN PENNELLA. 



AF 



J. KOBEN & D. C, DANIELSSEN. 



SYS 



PENNELLA BALÆNOPTEBÆ, Nob. 

 (Tab. 16, Fig. 1—9). 



I lange Tider henstod i Bergens Museum en Stump af 

 en Pennella, der ifølge Korens Meddelelser var funden 

 paa et varmblodigt Dyr, nemlig Balænoptera rostrata, 

 Fabr. Ved Naturforskermødet i Christiania 1844 fore- 

 viste Korens Medarbeider og Ven, Baron M. W. v. Düben, 

 et lignende Stykke, som ogsaa var uden Hovedpartiet, 

 — og knyttede nogle Bemærkninger dertil. Nogle Aar 

 senere fik vi et helt Exemplar, som vi da undersøgte, lod 

 tegne og kaldte det Pennella Balænopteræ. Med dette 

 Navn har det staaet i Museets Samlinger mindst i 20 Aar. 

 Efterhaanden ere flere komne til. 



I Steenstrups og Lütkens Skrift over det aåbne Havs 

 Snyltekrebse og Lernæer have disse Forfattere beskrevet 

 og afbildet en PeDnella, der findes paa Døglingen (Hy- 

 perooden rostratus, Chem.), hvilken de have benævnt 

 Pennella crassicornis. Dette er altsaa den anden Snylte- 

 krebs, som er funden paa varmblodige Dyr. Den har no- 

 gen Lighed med vor Art; men efterat vi have kunnet 

 ved Hjælp af Originalexemplarer anstille Sammenlignin- 

 ger, viser P. crassicornis sig dog at være forskj eilig fra 

 P. Balænopteræ, som vi nu skulle beskrive. 



Den forreste Del, det egentlige Hovedparti, er noget 

 bredere end langt, men nærmer sig forresten Kuglefor- 

 men. Paa Hovedets øverste Del, der er plan-convex, iagt- 

 tages en Mængde faste, glatte, næsten coniske Papiller, 

 som ere størst til Siderne og blive mindre, jo nærmere 

 de komme Centrum (Tab. 16, Fig. 7 a). Dette, som er 

 lidt fordybet, er forsynet med en liden, rund Aabning 

 (Mundaabningen). Papillerne strække sig mere hen- 

 imod Bug- end Rygfladen, hvorved denne bliver noget 

 længere end hin. Hvor Papillerne støde til Rygfladen, 

 findes i Almindelighed et Par af dem at være meget frem- 

 ragende, og danne ligesom Grændsen bagtil, eller, om 

 man vil, en bagre Rand. Under denue er en temmelig 

 dyb Grube, paa hvis nederste Rand sidde to meget korte 

 Antenner, hvis yderste Led ere forsynede med en liden Klo 

 (Tab. 16, Fig. 9 a); forøvrigt er den bagerste Flade glat, 

 plan i Midten, men lidt hvælvet til Siderne. Den for- 



A NEW SPECIES 



OF 



THE GENUS PENNELLA. 



BY 



J. KOREN & D. C. DANIELSSEN. 



PENNELLA BALÆNOPTEBÆ, Nob. 



(Tab. 16, fig. 1—9). 

 l\ or a long time there was in the Museum of Bergen a 

 fragment of a Pennella, which, according to Koren's 

 communication, was found on a warm-blooded animal, 

 namely Balænoptera rostrata, Fabr. At the meeting of 

 the Naturalists in Christiania in 1844, Koren's collaborator 

 and friend, Baron M. W. von Duben, exhibited a similar frag- 

 ment, which was likewise without the head-part, and pre- 

 sented some remarks in connexion with the same. Some 

 years afterwards we obtained an entire specimen, which 

 we then examined, delineated, and named Pennella Balæn- 

 opteræ. Under this name it has stood in the collection 

 of the museum for at least 20 years. Other specimens 

 have gradually been added. 



In Steenstrups and Lütkens work on the parasitical 

 crustaces and Lerneæ of the open sea, these authors 

 have described and delineated a Pennella which is found 

 on the Hyperoodon rostratus, Chem., and which they have 

 named Pennella crassicornis. This is therefore the second 

 Lerneæ which has been found on warm-blooded animals. 

 It has a great resemblance to our species; but after 

 having been enabled by help of original specimens to 

 institute comparisons, we find that P. crassicornis is never- 

 theless different from P. Balænopteræ, which we shall 

 now proceed to describe. 



The anterior part, the proper head-part, is somewhat 

 broader than it is long, otherwise approaching to the 

 globular form. On the upper part of the head, which 

 is plano-convex, there appear a number of firm, smooth, 

 nearly conical papillæ, which are largest at the sides, and 

 become smaller the nearer they approach to the centre 

 (Tab. 16, üg. 7 a). In the centre, which is slightly con- 

 cave, there is a small circular aperture (the oral aperture). 

 These papillæ extend more towards the ventral than 

 towards the dorsal surface, whereby the latter becomes 

 rather longer than the former. Where the papillæ join 

 the dorsal surface, a pair of them usually are found 

 to be very prominent, forming, as it were, the posterior 

 limit, or, so to say, a posterior margin. Under the latter, 

 there is a rather deep excavation, on the lower margin 

 of which there are two very short antennæ, whose ex- 

 treme joint is furnished with a little claw, (Tab. 16, 



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