15 



Ligesom de fleste mi(croiieIh(-a.vtev er ogsna denne 

 underkastet betydelig variation. 



Paa hoiarktiske eksemplarer lean zoocierne naa en 

 usædvanlig størrelse. Paa en koloni fra St. 223 liar jeg 

 saaledes maalt : 



Zoociets længde 1.-2 mm. 



„ bredde , 0.47 - 



Mundingens bredde 0.:!6 - 



Aviculariets længde fra niandihrlledet 0.2 



„ bredde 0.12 - 



Lignende maal liar jeg tåget paa en koloni fra Jokel- 

 fjord (Kvænangen) : 



Zoociets Lengde . . 1.0 mm. 



,, bredde . . 0.42 - 



Mundingens bredde . 0.2fl - 



Proximalrandens mucro er meget forskjellig i sin nd- 

 vikling, og mundingen kan tildels have et lejrimlia-li^nende 

 udseende (fig. 15). Zoociernes væg er i regelen tydelig 

 perforeret. Derimod kan oocieriie undertiden give indtryk 

 af at være hele (fig. 13), i andre tilfældo er perforeringen 

 paatagelig (fig. 14). Selv hos kolonier med ganske jevnbredo 

 zoocier har jeg seet tydelige huller i oocierne. Oociernes 

 form er heller ikke konstant, idet ganske kuglerunde kan 

 veksle med ovale. Avicularierne mangler i regelen, og 

 naar de forekommer sidder et dels paa høire side, dels 

 paa venstre side af mundingen, eller der kan ogsaa optræde 

 et paa hver side (fig. 14). Mandibelen er hut, og avicu- 

 larierne danner som oftest en ret vinkel med zoociets 

 længderetning. Hincks (9) har le ver et en figur af sin art 

 Mncwnella prceluciila, som leder tanken hen paa sincera- 

 arten. Af denne sidste har Hincks muligens kun seet 

 Ze^?'a??a-lignende former (se lO. tal) 11. fig. 3), og da var 

 det naturligt at opstille præhicida som en egen art, men 

 har man seet i hvilken grad M. sincera kan variere, bliver 

 man tilbøielig til at opfatte iwælucida som en varietet af 

 denne. „The peculiar projections, placed on each side of 

 the cell" (Hincks, 11, p. 225) var muligens ikke fuldt ud- 

 viklede avicularier (se 9, tab. 4, fig. 1). og skulde den for- 

 modning være rigtig, faar præhicida fra Queen Charlotte 

 Islands en paafaldende lighed med sincera fra det nordlige 

 ishav. I ethvertfald er M. sincera udbredt fra Novaja 

 Semlja til Gronland, og fra Spitsbergen til Lofoten. Paa 

 min reise vinteren 1899 tog jeg nemlig en koloni ved Di- 

 germulen i Paftsundet, 



Gen. Palmicellaria. 



Palmicellaria skenei, Ell. < t Sol. 



EscJiara slenei var. tridens, Busk (3), p. 33, fig, 3. 



Cellepora fridens. Kirchenjjauer (Biyozoa, Die Expedition 

 zur pliysikaliscii-cheniischen und Ijiologi- 

 schen Untersucluing der Nordsee im 

 Sommer 1872, p. 188. fig. a, b). 



Findesteder. St. 290, 223, 323, 363. 



Like most of the Mucronella species, this is subject 

 to considerable variation. 



In extreme arctic specimens, the zoæcia sometimes 

 attain an unusnal size. In one colony, for instance, from 

 Station 223, I have found the following measurements: 



Length of zoæcium 1.2 mm. 



Breadth of zoæcium 0.48 - 



Breadth of aperture 0.36 - 



Length of avicularium from niandibular joint . 0.2 

 Breadth of avicularium 0.12 - 



I have tåken similar measurements from a colony 

 from Jokel Fjord (Kvænangen) : 



Length of zoæcium . 1.0 mm. 



Breadth of zoæcium . . 0,42 - 

 Breadth of aperture . . 0.2!) - 



Tiie mucro of the proximal margin is very varied in 

 its development, and the mouth has sometimes a Lepralia-Ytike 

 appearance (fig. 15). The wall of the zoæcia is generally 

 perforated. The oæcia, on tiie other liand, sometimes give 

 the iinpression of being en tire (fig. 13); in other cases the 

 perforations are evident (fig. 14). Even in colonies with 

 zoæcia of equal breadtli, I have seeu distinct holes in the 

 oæcia. Nor is the shape of the oæcia constant, as quite 

 spherical sometimes alternate with oval. The avicularia 

 are generally wanting, and when they occur, are situated 

 on the right, or the left of the aperture, or one may 

 appear on each side (fig. 14), The mandible is not tape- 

 ring. and the avicularia are generally at right angles 

 to the longitudinal axis of the zoæcium. Hincks f9) has 

 given a figure of this species MncroneVa præhicida which 

 recalls the sincera sjDecies. It is possible that Hincks 

 has only seen forms resembling Lepraha (see 10, Pl. II, 

 fig. 3), and it would then be natural to make prælucida 

 info a special species; hut any one who has seeu to what 

 an extent il/, sincera can vary, will he inclined to look 

 upon præhicida as one of its varieties. "The peculiar pro- 

 jections, placed on each side of the cell" (Hincks 11, p, 

 225), were possibly avicularia that were not lully developed 

 (see 9, Pl, IV, fig. 1): and should this supposition be cor- 

 rect. the ijræhicida from Queen Charlotte Islands acquires 

 a striking resemblance to the sincera from the northeru polar 

 sea. In any case, M. sincera is di.stributed from Novaja 

 Semlja to Greenland, and from Spitsbergen to Lofoten. 

 While on my journey in the early part of 1899. I found 

 a colony at Digerinulen in Eaftsund. 



Gen. Palmicellaria. 



Palmicellaria skenei. Ell, Å Sol. 



Eschara skenei var. tridens, Busk (3), p, 33, fig. 3. 



Cellepora tridens, Kirchenpauer (Bryozoa, Die Expedition 

 zur physikalisch-chemisclien und biologi- 

 sclien Untersuchung der Xordsee im 

 Sommer 1872, p. 188, figs. a, b). 



Occurrence. St. 290, 223. 323. 3G3. 



