71 



* 



cation af Ambulacralskelettet kommer, som vi alt have 

 seet, denne Forandring ogsaa istand, ved hvilken Suge- 

 fødderne blive stillede i 4 istedetfor i 2 Rader. Nylig 

 har ogsaa Stimpson (Proceedings of the Boston Soc. of 

 Nat. Hist, vol. 8, pg. 261) begyndt at røre ved den af 

 Müller og Troschel etablerede, i saa mange Aar urokkede 

 Inddeling af Asteriderne, ved at vise, at det af dem som 

 characterise skt for Asteracanthiadernes Familie angivne 

 Antal af 4 Rader Sugefødder aldeles ikke er gjennemgri- 

 bende, idet lian fandt nogle Arter med 2, andre med 6 

 og 8 saadanne Rader. Stimpson foreslaar derfor for 

 denne Familie Navnet Pycnopodidæ. Dette Exempel viser 

 ligesom det af vor Pteraster noksom, hvor misligt det er 

 at begrunde Inddelinger i hvilkensomhelst Dyregruppe 

 paa en eneste Character alene. 



Vor nye Art vil kunne characteriseres paa følgende 

 Maade: 



Discus tumidiusculus, brachia breviora, radio disci 

 (in tripollicari) ad eundem brachiorum ut 1 J 1V 2 . Pax- 

 illi dorsales velut in P. pulvillo, sed majores, in centro 

 apicis aciculis coronati acicula ceteris longior multoqve 

 validior. Tessella madreporiformis costis ornata radian- 

 tibus, utrinqve dense obliqve striatis. Tentacula respira- 

 tionis iis P. pulvilli similia, sed majora, cylindrica apice 

 truncato, lobulis obsita rotundatis, ad apicem crebrioribus 

 inferneqve rarioribus, in verticillis 4— 5 dispositis. Pedes 

 suctorii in sulcis ambulacralibus latis magni, numerosis- 

 simi (circiter 150 in qvoqve radio), qvadriseriales. Pinnæ 

 transversales pedes suctorios numero æqvantes, alterna- 

 tim longiores pauloqve breviores, spinis 5 munitæ, exteri- 

 oribus longioribus; margine libero lobulis ornato incras- 

 satis carnosis, supra spinas longe prominentibus, lingula- 

 tis seu sublanceolatis, irregulariter sinuosis vel plicatis. 

 Pinna transversalis intima cum eadem de sulco ambula- 

 crali vicino margine laterali connata itaqve angulum ora- 

 lem formans. Spinæ marginales velut in P. militari et 

 P. pulvillo sat longæ. — Color dorsi sordide fusco - flavus, 

 margine cinereo-albido, ventris flavido- albus lineis paral- 

 lelis aurantiacis a pinnis transversalibus ad marginem 

 disci brachiorumqve currentibus; pedes suctorii læte vio- 

 lacei apice albo. Diametros 3". 



Habitat rarissimus in freto Dröbachiensi, profunditate 

 60 orgyarum. 



FORKLARING AF FIGURERNE. 



Tab. 8, Fig. 1 forestiller Pteraster multipes seet fra Bugsiden i na- 

 turlig Størrelse; a Munden; b den vifteformige Finne ved 

 Mundvinkelen; c Sugefødderne; d de paa Siderne af Bug- 

 furen beliggende Tværfinner; e den regelmæssigt foldede 

 Bugflade. 



Fig. 2. Samme seet i Profil (en afStraalerne er skaaret af, for at 

 vise Hulrummet mellem begge Ryggens Huder); a de co- 

 niske Vorter paa Ryghuden; b den ydre Ryghud; c Suge- 

 fødderne; d Ambulacral- Am pullerne; e Ambulacralskelet- 

 tet; f den indre Ryghud; g Indvoldshulen ; h Ovarierne; * 

 Randbræmmen; k Øiepletterne. 



Fig. 3. Tværsnit igjennem Ryggens Huder, forstørret; a den ydre 

 Ryghud; b den indre Ryghud ; cPaxillernes Skaft; d Paxil- 

 lernes Krone; e Respirationsrørene. 



skeleton this alteration is effected as we have seen, where- 

 by the water-feet are placed in 4 instead of in 2 rows. 

 Stimpson has also lately (proceedings of the Boston 

 Soc. of. Nat. Hist., Vol 8, p. 36) begun to disturb the 

 classification of the Asteridæ established by Müller and 

 Troschel and unimpeached for so many years, by shew- 

 ing that the number of 4 rows of water-feet indicated by 

 them as characteristic of the family of Asteracanthiadæ 

 is not at all constant; as he found some species with 2, 

 and others with 6 or 8 such rows. Stimpson suggests 

 therefore for this family the name Pycnopodidæ. This 

 instance shews, as does also that of our Pteraster most 

 conclusively, how injudicious it is to found classifications 

 in any group of animals on one single character. 



Our new species may be characterised in the fol- 

 lowing manner: 



Discus tumidiusculus, brachia breviora, radio disci 

 (in tripollicari) ad eundem brachiorum ut. 1 J iy a . Paxilli 

 dorsales velut i P. pulvillus sed majores, in centro apicis 

 aciculis coronati acicula ceteris longior multoque validior. 

 Tessella madreporiformis costis ornata radiantibus, utrin- 

 que dense oblique striatis. Tentacula respirationis iis P. 

 pulvilli similia, sed majora, cylindrica apice truncato lo- 

 bulis obsita rotundatis, ad apicem crebrioribus inferneque 

 rarioribus ; in verticillis 4—5 dispositis. Pedes suctorii 

 in sulcis ambulacralibus latis magni numerosissimi (circiter 

 150 in quoque radio) quadriseriales. Pinnæ transversales 

 pedes suctorios numero æquantes, alternatim longiores pau- 

 loque breviores, spinis 5 munitæ, exterioribus longioribus; 

 margine libero lobulis ornato incrassatis carnosis, supra 

 spinas longe prominentibus lingulatis seu sublanceolatis 

 irregulariter sinuosis vel plicatis. Pinna transversalis intima 

 cum eadem de sulco ambulacrali vicino margine laterali 

 connata itaque angulum oralem formans. Spinæ marginales 

 velut in P. militari et P. pulvillo sat longæ. Color dorsi 

 sordide fusco-flavus, margine cinereo-albido, ventris flavido- 

 albus, lineis parallelis aurantiacis a pinnis transversalibus 

 ad marginem disci brachiorum que currentibus pedes suc- 

 torii læte violacei apice albo. Diametros 3". 



Habitat rarissimus in freto Dröbachiensi profunditate 

 60 orgyarum. 



EXPLANATION OF THE FIGURES. 



Tål). 8, fig. 1. Represents Pteraster multipes viewed from the ven- 

 tral side, natural size; a the mouth; b the fan-shaped fin 

 at the buccal angle; c the water-feet; d the transverse 

 fins situated on the sides of the ventral furrow; e the 

 regularly folded ventral surface. 



Fig. a. The same in profile (one ray is cut off in order to show 

 the cavity between both cuticles of the dorsal skin); a 

 the conical warts of the dorsal skin; b the outer cuticle; 

 c the water-feet; d the ambulacral ampollæ; e the am- 

 bulacral skeleton; f the inner cuticle of the back; g the 

 perivisceral cavity; h the ovaries; i the marginal rim; 

 k the eye-spots. 



Fig. 3. Transverse section through the dorsal skin, magnified; a 

 the outer cuticle; b the inner cuticle; c the shaft of the 

 paxillæ; d the crown of the paxillæ; e respiratory tentacles. 



