KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:() 2. 83 



but inay abut by its corners on inferradials. 1. ant. ann not niucli stouter than the 

 larger branches of all the axil-arms; äpparently simple. Ant. and 1. post. arms have 

 inainaxils uj) to Vax, but only four axil-arms are visible. IBr 2. Axil-arms follow the 

 normal type; adanal /?Br and ; Br much stouter than other arrn-branches. The latter are 

 partly seen from the exteriör, but are squeezed into a more or less quadrangular shape. 

 The internodes are slightly constricted. Hinge with cross-processes distinct. Shagreen 

 ornament slight. Curvature of stem-ossieles slight. 



This species is founded on 3 crowns, more or less complete. 



Description. 



General appearanee of erown massive, the arms irregular and robust, like a hand 

 armed with the cestus, whence the trivial name. 



Dorsal cup. — The general outline as seen from 1. ant. radius is roughly quadrang- 

 ular and low, with a slight constriction ' ., way up; it narrows above owing to the slope 

 of the articular facet of the large radials. The measurements are, — height, 7.5 mm.; 

 width 10 mm.; thiekness, 7.5 mm. The height of the cup is to the length of the arms 

 as 15 to 48. The 1. ant. and r. post. faces are at an angle of about 40°. 



Base, shown in two specimens, in general contour much resembles that of C. got- 

 landicus, but has perhaps a slightly more obtuse angle opposite the hinge margin. Its 

 width along the hinge is 8 mm.; its height from stem to hinge 4 mm. 



BB. — 3 observed. Left basal oecupies rather less of hinge-line than in C. got- 

 landicus; its width is (5. o mm.; its height 4 mm. or perhaps a little more, as it reaches 

 right up to the stem and possibly enters the stem-facet. The sinuosity of the suture be- 

 tween it and the other basals is more marked than in C. gotlandicus, there being near its 

 äpex a reöntrant curve, and the apex itself being a rounded tongue. 



The stem is attached to post. and r. ant. BB, and äpparently touches the left basal 

 on the one side, while on the other it abuts on the T-piece; in other words, the posterior 

 angle of the base is coincident with the outer semicircle of the articular circumference. 

 The length of the outer side of the basals, from the stem to the end of the hinge, is 

 -1.5 mm. or 5 mm. The diameter of the stem-articulation is 3.25 mm.; the axial canal is 

 äpparently in the centre, or perhaps a little towards the anal tube. 



RR. — 1. ant. R: the two halves are 1 mm. apart; the lower half is of ogiva] 

 shape like a bishops mitre; its base is about 3 mm. long, its height, 3 mm. and 4.5 inni. 

 in the two specimens. The upper half is an obtuse-angled triangle, with a slightly ex- 

 cavated base of 5.5 mm.; its height is 1.8 mm.; the sides have a slight convex curve. 



Large radials: general appearanee much as in C. gotlandicus. Ant. R is 7-sided, 

 being bounded as follows. — (1) by articular facet, with a slight concave curve, support- 

 ing IBi-j and part of IBr 2 , 5 mm.; {2) by r. ant. B', with concave curve, 3.25 mm.; (3) by 

 r. ant, B. and left B (hinge-line), 3 mm.; (4) by r. ant. \V, concave curve, 5 min.; (5) 

 by 1. post. R, 1 mm.; ((>) by 1. ant. R*, and 1. ant. IBr,, concave curve, 5.25 mm.; (7) 

 by the right-hand IlBr, of ant. arm, 1 mm. The extreme height of this plate is 8 mm. 



