118 



den, saa at der kan dannes et temmeligt tykt Coenenchym, 

 hvortil Polyperne med deres Basaldel ere stærkt bundne, 

 Tab. XXI. Fig. 9, 11. 15. En saadan Gruppe ai Polyper 

 har et ganske eiendommelig! Ddseende, da den ikke er 

 fæstet til Noget, men ligger los i Sandet. Den ovre Flade 

 er lidt konkav, idet Polyperne reise sig fra et Midtparti, 

 Tab. XXI, Fig. 11, 14, der dannes af et Coenenchym. 

 som fremstaar derved, at Polypernes Basaldele ere smeltede 

 sammen; den undre Flade er konvex, temmelig jævn, 

 men antyder ved fine Linier de Steder, fra hvilke Polyperne 

 ere udgaa.ede. Tab. XXI, Fig. 12. 15. Vi skulle senere 

 se, hvorledes Polyperne korrespondere med hinanden; kun 

 her skal antydes, at hvor 2 eller 3 ere forenede, og en 

 af Polyperne trykkes sammen, svulmer den anden og tredie 

 op, idet Fluidumet fra den enes Gastrovascularhulhed gaar 

 over i de andres, men hvor der er 6— 8 sammen, er Kom- 

 munikationen ikke saa let paa viselig. 



Polypkroppen er stærkt inkrusteret af Saml. der gjør, 

 at Huden foles fast og noget ru. men er forresten jævn, 

 det vil sige ikke rynket; opimod Kroppens øverste Rand 

 sees 18 bladformige, inkrusterede Ribber, som strække sig 

 til Mundskivens ydre Raud. og imellem hvilke Huden sees 

 at være nøgen, Tab. VI. Fig. 1: Tab. XXI. Fig. 11. 12. 

 15. Xaar Dyret er indtrukket, forme disse bladformige 

 Ribber sig til 18 Straaler. der konvergere mod Mundskiven, 

 Tab. XXI. Fig. 3, 4. 14. Denne er plan. meget bred. ikke 

 inkrusteret, men forsynet med 18 fine Folder, som gaa fra 

 den indre Teniakelrække til den aflange Mund. der er 

 noget fremstaaende og har en svag Mundvig (Gonidiefure), 

 Tab. XXI, Fig. 14. 



Tentaklerne staa i to Rækker, 18 i hver; de ere 

 slanke, noget hengere end Skivens Bredde, især gjælder 

 dette den indre Række, som staar paa Mundskivens ydre 

 Rand, Tab. VI, Fig. 1; Tab. XXI, Fig. 11. 14. Saavel 

 Mundskiven som Tentaklerne kunne fuldstændig drages ind 

 i Kroppen! 



Polypkroppene eie i deres Udspring, førend endnu 

 Tentaklerne og Mundskiven er dannet, i Regelen halvkugle- 

 formede og meget stærkt inkrusterede. 



Farven varierer noget efter de forskjellige Lokalite- 

 ter. Kroppen er let brunrød, næsten teglstensrød; Tentak- 

 lerne lysere, brunrøde, giennemsigtige. Mundskiven endnu 

 lysere end Tentaklerne. og omkring Mundskivens ydre Rand, 

 lige ved Grunden af den indre Tentakelrække er en smal. 

 lys rosenrød Ring, Tab. VI, Fig. 1. Dette er Regelen; men 

 der findes Individer, hvis Farve er graaliggrøn, spillende i 

 det Violette. Tab. VI. Fig. 2. 



De anatomisk-histologiske Undersøgelser frembyde 

 adskillige Vanskeligheder paa Grund af, at Huden er saa 

 stai kt inkrusteret af Sand (Kisel), at gode Tversnit ikke 

 er let at erholde. Dr. Erdmann udtrvkker sic; med Hensyn 



the connection between them increases considerably in 

 breadth, so that a pretty thick sarcosoma may be formed, 

 to which the polyps are firmly attached by their basal 

 portion, (Pl. XXI, fig. 9, 11. 15). Such a group of polyps 

 has quite a peculiar appearauce, as it is not adherent to 

 anything but lies loose in the saml. The superior surface 

 is a little concave, owing to the polyps rising up from a 

 portion in the middle (Pl. XXI. fig. 11. 14). formed of a 

 sarcosoma produced by the basal portions of the polyps 

 concreting together; the inferior surface is convex and 

 pretty even. but indicates by fine lines the spots from 

 which the polyps have issued (Pl. XXI. fig. 12. 15). We 

 shall subsequently see how the polyps correspond with 

 earl i other, but here we shall only indicate, that where 2 

 or 3 are united, and one of the polyps is contracted, the 

 second and third ones swell up. owing to the fluid from 

 the gastro-vascular cavity of the one passing into the 

 cavities of the others, hut where there are (i — 8 polyps 

 together. the eonnnunieation between them is not so easily 

 distinguished. 



The body of the polyp is strongly encrusted with 

 sand. causing the integument to feel finn and somewhat 

 rough, but otherwise it is even. that is to say not wrinkled. 

 Towards the uppermost margin of the body 18 foliform, 

 encrusted ribs are visible, which extend themselves to the 

 outer margin of the oral disc, .nid between these the in- 

 tegument is seen to he li.ire (Pl. VI. rig. 1; Pl. XXI, fig. 



11, 12. 15). When the animal is contracted those foli- 

 form ribs resolve themselves into 18 rays, which converge 

 towards the oral disc (Pl. XXI. fig. :;. 4. 14). The oral 

 dise is plane, very broad, not encrusted, but furnished with 

 18 line folds that |>ass from the inner tentacular series to 

 the oblong niouth. which latter is somewhat prominent and 

 has a taint oral angle (gonidial-groove) (Pl. XXI. rig. 14). 



The tentacles are placed in two series. 18 in each ; 

 thev are slender. and somewhat longer than the breadth 

 of tin- disc: this is especially the case with the inner series, 

 phued on the outer margin of the oral disc (Pl. VI, fig. 1; 

 Pl. XXI. fig. 11. 14). Botli the oral disc as well as the 

 tentacles may be completely withdrawn into the body. 



The bodies of the polyps are, at their commencement, 

 before the tentacles and the oral disc have vet been formed. 

 usually semispherical in fonn, and very strongly encrusted. 



The colour. This varies somewhat according to the 

 different localities. The body is light brownish-red, almost 

 brick-colour. The tentacles lighter-coloured, brownish-red, 

 and transparent. The oral disc is still lighter in colour 

 than the tentacles. and round the outer margin of the oral 

 disc. exaeth ;it the hase of the inner tentacular series, 

 there is a narrow. light-coloured, rose-red annulus i Pl. VI, 

 fig. 1). That is the rule, but there are also found sorae 

 individuals whose colour is greyish-green, with a violet play 

 of colour (Pl. VI, fig. 2). 



The anatomo-histological examination presents con- 

 siderable difficulties, owing to the fact that the integument 

 is so strongly encrusted with sand (Silex) that satisfactory 

 seetions are not easy to obtain. Dr. Erdmann expresses 



