KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 2. 91 



The oceurrence of this extreme form is of interest; but, while the material is so 

 limited, I refrain from naming this speeies. 



Calceocrinus nitidus, n. sp. 



(Plate IV, tigs. 117—122.) 



(?) 1878. Cliirocrinus gotlandicus, Angelin, Iconographia, Tal». XVI, figs. 10, 11, 12, 13, 14, not 

 tigs. 6, 7, 8, 9. 



Diagnosis. 



Proportions of cup are, — height 1; width 1.36; width at hinge 1.27; thickness 0.97. 

 Cup seeu from 1. ant. radius quadrangular, low, with no lateral constriction. 1. ant. R s 

 and R' separate. T-piece extreinely small, linear; sunk right down between inferradials. 

 x rests on remains of T-pieee and of inferradials. 1. ant. arm verv little stouter than 

 adanal branch of primaxil arm: apparently simple. Ant. and 1. post. arms have mainaxils 

 up to Vlax. IBr 1. Axil-arms follow normal type; their larger branches gradually de- 

 crease in size; first and seeond internodes are slightly constricted; the remaining ossieles 

 are moniliform; abanal branches minnte, and only visible on exteriör at their point of 

 origin. Hinge wide and deep, with ven' faint traees of cross-processes. No trace of 

 ornament. Stem? 



This speeies is founded on two specimens, - - (a) a fairly complete crown, drawn 

 in Angelin's MS., ]>. 136; (b) a cup with part of the arms, from which Angelin made 



an analysis, MS., p. 137. 



Description. 



General appearance of crown neat and elegant; hence the trivial name. 



Dorsal enp: The genera] outline, as seen from 1. ant. radius, is low and quadran- 

 gular, with no lateral constriction. The measurements are, — in a, height 4.75 min.; 

 width 6.3 ram.; thickness 4.5 mm.: in b, height 6 mm.: width 9 mm.; thickness 6 mm. 

 The height of the cup is to the length of the arms as 9 to 48, i. e. less than in previous 

 speeies. The 1. ant. and r. post. faees are parallel. 



Base: In a the width is 5.75 mm.; the height is "2.25 mm. In l> the width is 8 

 mm.; the height is 3.2 mm. 



Basals, 3 observed. Left basa! in a does not quite reach the stem-facet; in b it 

 takes a small part in it; it occupies less of the hinge-line than in previous speeies; in <i 

 its width is 4.25 mm., its height 3 mm.; in b its width is 6 mm., its height 3 mm. The 

 sutures between the left basal and the other basals are sinuous in a, straight in b. 



Stem-facet markedly concave as in C. tenax; or rather, each basal that enters into 

 it slopes down towards the axial canal. The facet is not so elose to the edge of the basals 

 as in C. pugil, C. tucanus, and C tenax, and does not abut on the radials. The r. post- 

 B is more clear in b than in a. 



Radials: 1. ant. R, — the two halves are separated, in a by 0.5 mm., in b by 

 1.25 mm.: the inferradial is of mitre-shape, but in a a small tongue projects towards the 



