ANTEDON ANGUSTICALYX. 289 



Centro-dorsal hemisplicrical, rather flattened at the dorsal pole, and bearing twenty to twenty- 

 five cirri. These have about twenty joints, a few of which are longer than wide; the later ones 

 are somewhat compressed laterally and more or less distinctly carinate; the penultimate with an 

 opposing spine. 



First radials partially visible above the angles of the centro-dorsal; the second short, sharply 

 convex, and closely united laterally. Axillaries short, broadly pentagonal, and very convex in the 

 centre, forming a median tubercle with the second radials. 



Three distichals with a syzygy in the axillary, which is in close contact with its fellow on the 

 next ray, and another syzygy between the first two brachials. These five joints, and in a less 

 degree also the two outer radials and the third brachials, are in close lateral contact and very dis- 

 tinctly wall-sided, with sharp edges and the margins of the dorsal surface a little depressed. The 

 second, and occasionally also the third, brachial may likewise be slightly flattened on both outer 

 and inner sides. One specimen has two palmars united by syzygy and another two with the axil- 

 lary a syzygy. 



Eleven to twenty arms of some one hundred and twenty joints, the lowest nearly oblong, and 

 the following ones triangular, as long as wide, and gradually becoming more quadrate. The 

 pieces of the calyx and the lower parts of the arms often have somewhat prominent edges. On 

 the arms, which start directly from the radial axillary, the third brachial is a syzygial joint, and 

 the next syzygy is between the fourth and the thirteenth brachials; but when distichals are pres- 

 ent the first two brachials are generally united by syzygy, and the next syzygial joint is from the 

 seventh to the tenth brachial. After this there is an interval of two to fifteen, usually four to 

 seven, joints between successive syzygia. 



The second distichal bears a small pinnule, 7mm. long, which consists of some twenty to 

 twenty-five short joints, the lowest of which, and especially the first, are wide, trihedral, and flat- 

 tened against the arm, while the remainder are slightly carinate. The next pinnule (on second 

 brachial) is a trifle longer, with relatively long terminal joints, and the basal ones less wide and 

 more carinate. The third and following brachials have still longer and stouter pinnules (12mm.), 

 with the outer edges of the third and the two to four following joints much produced towards the 

 ventral side, so as to give them a broad and flattened appearance. The length of the pinnules 

 decreases somewhat after the sixth brachial, but the expansion of their lower joint is traceable till 

 the fifteenth or twentieth, after which they become more slender, with only the two lower joints 

 wider than long. Disk much incised and completely plated, as are also the arms, both along the 

 ambulacra and at their sides. A pavement of anambulacral plates covers the genital glands. The 

 pinnule-ambulacra have well-defined side plates, alternating with and partly concealing the sac- 

 culi, which are mostly small. 



Colour in spirit: light whitish-brown. Disk 10mm.; spread 20cm. 



Schon aus dieser Gegeniiberstellung von Carpenters Beschreibungen der zwei 

 Arten geht deutlich hervor, dass die zwei Arten viele Charaktere gemeinsam 

 haben. Carpenter selbst kann sich dieser Einsicht nicht verschliessen und hebt 

 die innigen Beziehungen, welche zwischen beiden Species bestehen, ausdrucklich 

 hervor: "This species (A. angusticalyx) is readily distinguished from all other 

 tridistichate forms of Antedon, with the exception of A. inaequalis, with 

 which it has many characters in common" (p. 243), und fur A. inaequalis be- 

 merkt Carpenter: "This species is rather closely allied to A. angusticalyx, but 

 reaches a considerably larger size" (p. 245). — Fur den unbefangenen Beurtheiler 

 kann es keinem Zweifel unterliegen, dass die Begriindung der beiden Species auf 

 sehr schwachen Fiissen steht. Da uns jedoch die Originale Carpenters nicht 

 aus eigener Anschauung bekannt sind, enthalten wir uns hier eines entscheiden- 

 den Urtheils. 



Die beiden uns vorliegenden Exemplare stehen zwischen A. angusticalyx 

 und A. inaequalis, was aus Folgendem des Naheren hervorgehen wird. 



