13 



paa langs, og paa overfladeu er der smaa forhoininger, 

 svarende til hvert individ; disse sees igjennem, hvide op- 

 retstaaeude. 



Didemnum niveum, (Tiard. 

 Cormus er nielkehvid. '/..— I cm. tyk, findes som 

 overtræk paa tang og koraller. Overtiaden er ujevn, da 

 den bugter sig ud omkring hvert individs ingestionsaabning. 

 Stjerneformige kalkspicula er ndbredt overalt, men i over- 

 veiende mrengde langs koloniens overflade. 



Individerne sidder i et enkelt lag langs overtiaden og 

 lodret paa denne. 



Iiif/. (Kiliiihu/en liar 6 lapper. 



3 rækker gjællespalter tindes. Overgangen fra thorax 

 til abdonien er meget trang, og den skjules næsten af en 

 kugleformig ansamling af kalkspicula paa dorsalsiden. 

 Nedenfor udbreder abdomen sig til et volum, tiere gange 

 saa stort som thorax. 



Mavcu er glat. Ta.v defereiis gjor 7 — 8 slyngninger 

 om testikelen. 



Flere larver findes liggende i cormus, inden for det 

 overfladiske lag. 



Goodsiria coccinea, Cunningham. 



(Pl. IV. Hg. 32—34). 

 Syn. Goodsiria borealis, Gottschaldt? 



Af denne art blev der }iaa to forskjellige stationer 

 fundet en del kolonier, som varierer meget i størrelse. 

 Den største af kolonierne er afbildet af professor G. (). 

 Sårs i naturlig størrelse (fig. 32 a). Den største udstræk- 

 ning af ellipserne paa overfladen af denne varierer 

 mellem 3 mm og lU mm, medens afstanden mellem aab- 

 ningerne er temmelig konstant, 2 — 3 mm. 



De øvrige kolonier er mindre, ' lige ned til en, som 

 kun bestod af to individer, ca. 5 mm paa liver kant. 



Farven er paa levende kolonier jgulrod, paa spiritus- 

 eksemplarer graa med Idaaligt skjær. 



Begge aahni liger har 4 lapper, som ikke er lige store. 

 TeiitaMerne om ingestionsaabningen er lange, traadformige, 

 ca. 40 i antal. Omkring egestionsaabningen findes ogsaa 

 en række meget smaa, enkle tentakler. 



iUmmcrgruhen er bægerformig, og nervegangliet er 

 behggende et stykke bag denne; det er aflangt. 



OjæUesæMen er uden folder paa. siderne; rygfoJden 

 er en foldet, helrandet membran, temmelig bred. Saavel 

 længderibberne (4 paa hver side) som tverribberne er 

 membraner. De deler gjællesækken i lave rektangler med 

 5 — 6 stigmata i hvert. Feldtet nærmest rygfolden er nogct 

 bredere end de øvrige. 



The sides are corrugated longitudinally, and there are 

 small prfjininences on the upper surface, corresponding to 

 the individual members, whicii are in a vertical position, 

 and shine through white. 



Didemnum niveum, (^iard. 



The corriMs is of a milky white colmii-. from •/-■ f<' 1 

 centim. thick. It is found covering seaweed and corals. 

 Tiie surface is uneven, as it bulges out round the branchial 

 orifice of each animal. Stellate calcareous spicules are 

 scattered all over, most tliickly along tiie u])per surface of 

 the colony. 



The sejtarate members lic in a single layer along tlie 

 uppor surface, and perpendicular to it. 



The hranchial orifice is 6-lobed. 



There are 3 rows of branchial stigmata. The transi- 

 tion from tlu' tliorax to tiie abdonien is very narrow, and 

 almost liidden by a globular accuniulation of calcareous 

 spicules on the dorsal side. Below, the abdomen exjiands 

 to a bulk several times as large as that of the thorax. 



The atomacli is sniootli. The rff.s- deffrens makes 7 

 or 8 windings round the testicle. 



Several larvæ are lying in the test, below the super- 

 ficial stratum. 



Goodsiria coccinea, Cunningiiam. 



(Pl. IV, tigs. 32— ::!4). 

 Syn. Goodsiria borealis, Gottschaldt ? 



A few colonies of this species were found at two 

 diftereiit stations, varying greatly in size. The largest of 

 the colonies has been figured by Prof. G. 0. Sårs, the 

 natural size (fig. 32 a). The greatest extent of tlie ellipses 

 on its surface varies bctween 3 and 10 niillim., while the 

 distance between the apertures is generally constant, viz. 

 2 or 3 millim. 



The other colonies are smaller, one consisting of 

 only 2 members, each edge measuring about 5 millim. 



In tile living colony tiie colour is a yellowish red, in 

 preserved specimens it is grey with a bluish tinge. 



Both the aperfxres have 4 lobes, which are unequal 

 in size. The tenfacles round the oral orifice are long and 

 filiform, numbering about 4(1. There is also a fringo of 

 very small simple tentacles round tiie atrial orifice. 



The dorstd f uherde is cup-shaped, and the nerve 

 ganglion, which is oblong, is situated a little behind it. 



The hranchial sac has no folds on the sides; the 

 dorsal lamina is a folded, rather broad, plain membrane. 

 Both the longitudinal bars (4 on each side) and the trans- 

 verse bars are niembranes. Tiiey dividc tlie brancliial sac 

 into low rectangles, witli 5 or 6 stignnita in eacli. The 

 compartment nearest to the dorsal lainina is rather broader 

 than the others. 



