muskellaget og har on suadMii iidstrækning i horisontal ret- 

 ning, at (le nresten danner en sluttet ring. De er herma- 

 pliroditiske med æg og sperma ndviklet i foi'skjellige slyng- 

 ninger. Æggene er polygonale, ng hvert æg er oragivet af 

 et lag smaa foUikelceller. 



Den blev fnnden ved Reykjavik. 



Styela uniplicata, nov. sp. 



(I'l. IV, tiiT. lii— 20). 



Den er omtrent lige bred, som den er hoj, ca. 

 2 cm. paa hver kant. Den er fasthæftet med undersiden, 

 og begge aabningei- sees som hvide kryds paa oversiden. 

 Afstanden mellem disse er 7 mm. 



Kajjpen er paa spiritusexem.plarer graabrun, gjennem- 

 skinnelig og noget incrusteret med sand. Den har ogsaa 

 fine heftetraade, især paa undersiden. 



Åahiingerne har begge 4 lapper og er siddende. 

 Omkring ingestionsaabningen er der ca. 60 fenfaJiler, som 

 varier(>r noget i stoi'relse. De er alle enkle, traadtbrmige, 

 og de storste findes ret ind for hver af de fire grene af 

 krydset i aabningen. 



Flimmergruliens aabuing er halvcirkelformig og ligger 

 tilhøire for nervegangliets forreste del. Dette er næsten 

 tre gange saa langt som det er bredt, og udsender fortil 

 et par tykke nervetraade, som løber tæt udenom tentakel- 

 kransen. 



Gj(i:-llesæl'Jiens ri/gfold er en helrandet membran, 

 bugtet i kanten og l)oiet til venstre. Adskilt fra denne 

 ved et feldt paa 2 kengderiliber tindes paa hver side en 

 d\b fold, dannet af 10 Irengderibber Disse folder er saa 

 dybe, at de næsten stoder sammen inde i g^jællesækken, og 

 der dannes saaledes en rorformig kanal af den bagerste 

 del af denne. Henimod svælget trykkes denne kanal sam- 

 men fra siderne, saa dens hulrum aldeles forsvinder, og den 

 staar som en finne uden])aa gjællesækken. Mellem endo- 

 stylen og de nævnte folder er gjællesækken glat : men der 

 findes enkelte steder tætstillede længderibber. Dette er 

 tilfældet paa begge sider nær endostylen, 5 længderibber 

 fra denne, og desuden paa venstre side et sted længer inde; 

 det er hver gang 4 længderibber. som ei' rykket sammen. 

 Mellem endostylen og de dybe folder findes paa hver side 

 ca. 30 længderibber; disse er smale og rager ikke ind i 

 gjællesækken; de har et noget uregelmæssigt forløb. kan 

 Ijoie af til siden eller pludselig ophøre. Tverribberne er 

 af to størrelser. De storste af disse deler i forbindelse 

 med længderibberne gjællesækken i kvadratiske feldter. hvert 

 med 3-^4 stigmata. De mindste tverribber gaar over spi- 

 raklerne i regelen uden at dele dem. I feldtet mellem de 

 dybe folder og rygfoldeii breder tverribberne sig ud, og 

 stigmatarækkerne smalner af; samtidig gaar ogsaa spirak- 

 lerne over i hinanden. Paa hoire side af svælget findes 

 en sjjids læbe. 



tached to the rauscle stratnm. and extend so far in a hori- 

 zontal direction, that they form alniost a complete circle. 

 They are hermaphroditic, having ova and sjjerm developed 

 in diflVrent bends. The ova are polygonal, and each one 

 is surrounded by a laver of small follicles. 

 This species was fonnd at Reykjavik. 



Styela uniplicata, nov. sp. 



I n. ]\'. fi.js, Hl— iii). 



It is nearly as bi^oad as it is high, being about 2 

 centim. each way. It is attached by the under side, and 

 both apertures are visible as white crosses on the upper 

 surface, the distance between thcm being 7 miiliiii. 



In alcohol specimens tlie tunic is of a greyish brown 

 colour, translucent and somewhat incrusted with sand. It 

 has also fine attaching filaments, especially on the under 

 sui-facc. 



Both the ajicrtnres are 4-lobed and sessile, Around 

 the branrhial orifice there are about (iO tentarles. sonu'what 

 varying in size. They are all simple and filifoim. and the 

 largest are to be found immediately within each of the 

 four arms of the cross in the o])ening. 



The aperture of f J/e Oorsal tubercle is semicircular in 

 form, and is situated to the right of the foremost part of 

 the nerve ganglion, This last is almost 3 times as long 

 as it is l)road, and sends out in front a few thick nerve 

 fibres. which run just outside the fringe of tentacles. 



Tlie dorsal htuiuia of the hranchial sac is a plain 

 menibrane with a sinuous edge and curving to the left. 

 ()u each side of, and separatcd fiom it by a firld of 2 

 loniiitudinal bars. is a deep fold formed of Id longitudinal 

 bars. These folds are so deep that they almost meet in 

 the branchial sac, thereby forming out of the hinder portion 

 of the sac a tube-like channel. Towards the gullet, this 

 channel, is compressed at the sides, so that its cavity en- 

 tirely disappears, and it stands like a piraple outside the 

 branchial sac. Between the endostyle and the above-named 

 folds, the branchial sac is smooth; but in a few places 

 there are closely-set longitudinal bars. This is the case 

 on both sides near the endostyle, at a distance of .") longi- 

 tudinal l)ars from it. and also on the left side at a place 

 farther in: in each instance 4 is the number of longitudinal 

 l)ars that are ])ressed together. Between the endostyle and 

 the deep folds, there are about 30 longitudinal bars to be 

 found on each side; they are narrow, and do not project 

 into the branchial sac. They take a somewhat irregular 

 couise. and may turu otf to one side, or cease altogether. 

 The trausverse l)ars are of two .sizes. The larger of these, 

 in conjunction with the longitudinal bars, divide the bran- 

 chial sac into square fields, each with 3 or 4 stigmata. 

 The smaller transverse bars cross the spiracles without, as 

 a rule, dividing them. ln the space between the deep 

 folds aud the dorsal lamina, the transverse bars become 

 broader, and the rows of stigmata narrower, while at the 

 same time the spiracles are merged in one another. To 

 the right of the gullet there is a pointed lip. 



