Saavel Wyville Thomson som vi henførte vore Slægter 

 til Apiocrinidernes store Familie, ihvorvel vi antydede, at 

 baade Thomsons og vor Slægt, ligesom Slægten Rhizocrinus, 

 havde meget tilfælles med Slægten Bourguetierinus; men 

 Herbert Carpenter har nu med fuld Ret optaget dem i 

 LoricTs Familie Bourgueticrinidæ. Jeg skal nu levere en 

 Beskrivelse med saavidt mulig anatomisk-histologiske Under- 

 søgelser over Bathycrinus Carpenteri. 



Stilken er slank, hoi, temmelig boielig, tykkere for- 

 neden, smalere foroven, næsten cirkelrund paa den øverste, 

 lidt atlang paa den midterste og fuldkommen elliptisk paa 

 den nederste Trediedel. Roden er lang, mere eller mindre 

 forgrenet. Kronen (Hovedet) er 10-armet. Armene bære 

 Pinnuler, Tab. I, Fig. 1. 



Paa et Exemplar, hvor Stilken er 200""" høi, er denne 

 sammensat af 118 Led. Det øverste Led, som altid er det 

 længste — indtil 4'""' — er cirkelrundt, lidt udvidet opad, 

 hvorfra Basalerne udgaa, og paa unge Exemplarer sees 

 tydeligt, at dette Led egentligt bestaar af mange Led, der 

 ere sammensmeltede og have efterladt Spor af smale Ringe, 

 som alene kunne iagttages ved stærk Loupe, Tab. I, Fig. 

 2 a, 3 a. Under dette Led følger nu 4 — 8 ligeledes cirkel- 

 runde Led, der ere fra 0.5 — 1.0""" lange, og hvis Bredde 

 er lig med Længden, Tab. I, Fig. 2 b, 3 b. 



Nu begynde Leddene at blive længere og længere, 

 alt eftersom de komme ned paa Stilken, saa at de endog 

 ved Enden af den øverste Trediedel ere dobbelt saa lange 

 som brede, Tab. I, Fig. 2 c, 3 c. De ere i Regelen lige 

 tykke overalt, dog hænder det, at de ere lidt udvidede mod 

 Enderne. Leddenes saavel øverste som underste Flade er 

 næsten rund, Tab. I, Fig. 4. 



Fra Leddenes indvendige Vægge udgaar paa hver 

 Side, diametralt modsat, en temmelig bred Kalkkam, Tab. 

 I. Fig. 4 a, der gaar henimod Midten, hvor den kredsfor- 

 migt udvider sig og hjælper derved til at danne en cirkel- 

 rund Kalkkanal, som optager Midten af Leddefladen, og 

 hvorigjennem Centralstrængen løber. Tab. I, Fig. 4 b. 

 Denne Kalkkam er lidt hvælvet paa den ene Leddeflade. 

 og har en tilsvarende Fordybning paa den anden, hvorved 

 Leddet befæstes. Paa hver Side af Kalkkanalen sees en 

 stor, halvmaaneformig Hulhed, som tjener til Insertion for 

 Muskler og mangfoldige, senede Strænge, der holde Leddet 

 sammen og bidrage til dets ringe Bevægelighed, Tal). I, 

 Fig. 4 c, 5 a. 



Leddene paa Stilkens midterste Trediedel afvige kun 

 fra de nys beskrevne derved, at de ere noget længere. an- 

 tage en mere aflang Form, Tab. I, Fig. 2 d, 3 d, der især 

 er fremtrædende paa deres noget udvidede Ender, hvor 

 Leddefladen frembyder en tydelig aflang Figur, paa hvis 

 største Axe den før beskrevne Kalkkam danner en liden 

 Fremstaaenhed, som endog giver sig tilkjende paa Leddets 

 ydre Flade, Fig. 5 b. 



Both Wyville Thomson and we, assigned our genera 

 to the large family of Apiocrinidæ, although we indicated 

 that both Thomsons and our genus, like the genus Rhizo- 

 crinus, had much in common with the genus Bourguetieri- 

 nus ; but Herbert Carpenter has now, with perfect propriety, 

 included them in LorioFs family Bourgueticrinidæ *. I shall 

 now give a description accompanied. as far as possible, 

 with anatomo-histological observations on Bathycrinus Car- 

 penteri. 



The stalk is slim, high, pretty flexible, thickest below 

 and thinnest at the top, almost circular in its uppermost 

 part, slightly oblong in the middle portion, and completely 

 elliptic in the lowest third part. The root is long, and 

 more or less ramitied. The crown (the head) is 10-armed. 

 The arms carry pinnules. (Pl. I, fig. 1). 



In one specimen in which the stalk is 200""" in height, 

 it is composed of 118 joints. The uppermost joint, which 

 is always the longest one — as much as 4""" — ■ is circular, 

 a little expanded upwards. from which situation the basals 

 issue: and in young specimens it is distinctly seen, that 

 this joint really consists of many joints which have coalesced 

 and lett traces of narrow rings that could only be disting- 

 uished with the aid of a powerful magnifier (Pl. I figs. 

 2 a, 3 a,). Below that joint now come 4 — 8, also circular 

 joints, which are from 0.5 — 1.0"" in length, with a breadth 

 equal to the length (Pl. I, figs 2 b, 3 b,). 



The joints then begin to become_ longer and longer 

 — according as they descend on the stalk — so that at the 

 extremity of the uppermost third part they are even twice 

 as long as they are broad (Pl. I, figs. 2 c, 3 c). They are, 

 generally, everywhere the same in thickness, although it 

 sometimes happens that they are slightly expanded towards 

 the extremities. The uppermost, as well as the lowest 

 surfaces of the joints are almost round (Pl. I. fig. 4). 



From the inner walls of the joints there issues on each 

 side, diametrically opposite to each other, a pretty broad calca- 

 reous ridge (Pl. I, fig. 4 a) which passes towards the middle 

 where it expands annularly, and thereby aids in forming a 

 circular calcareous canal which occupies the middle of the 

 surface of the joint, and through which the central cord 

 runs (Pl. I, fig. 4 b). This calcareous ridge is slightly ar- 

 cuated on the one articular surface, and has a corres- 

 ponding depression on the other surface, by which the joint 

 is secured. On each side of the calcareous canal there is 

 visible a large peltiform cavity. which serves for the inser- 

 tion of muscles and multitudinous sinewy cords which 

 keep the joint together, and contribute to its small flexi- 

 bility (Pl. I, figs. 4 c, 5 a). 



The joints on the medial third part of the stalk only 

 differ from those just described, in being somewhat longer 

 and in assuming a more oblong form (Pl. I, figs. 2 d, 3d); 

 the difference being especially prominent in their somewhat 

 expanded extremities, where the articular surface presents 

 a distinct oblong figure, on whose greatest axis the calca- 

 reous ridge previously described forms a small projection 

 whose presence is even felt on the outer surface of the 

 joint (Pl. I, fig. 5 b). 



