KON 



GL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N'.0 2. 89 



Description. 



General appearance of crown like that of C. tucanus; but the larger arm-branches 

 are closelv pressed together and dräwn to a point, while the mainaxil series is closely 

 fitted to the anal plates. Thus one is reminded of a hand with the outstretehed fingers 

 tightlv closing aronnd a small object; hence the narae »tenax» (grip-fast). 



Dorsal Cup: The general ontline, as seen from the 1. ant. radins, is mneh as in 

 C. tucanus; but, as seen from the side, the facets of the large radials slope more, i. e. 

 make a smaller angle with the long axis. The measurements are, — height, B mm.; 

 width, 7.5 mm.; thickness, ö.2 inni. The height of the cup is to the length of the arms 

 as 11 to 48, the same as in C. tucanus. The 1. ant. and r. post. faees are at an angle 

 of 25°. 



Base as in C. tucanus; has a width of 6.25 mm., a height of 3 mm. 



Basals 4 observed. Left basal has a tongue 1 mm. long, projectirig from the body 

 of the plate and just reaehing the stem. 



Stetn-facet has much the same relations as in C. tucanus, but is more eoncave. with 

 the plates that enter into it sloping straight down towards the nxial canal. 



Radials: 1. ant., — the two halves are separated by 1.75 mm.; the inferradial is 

 2.5 mm. wide at the base, and 2.8 mm. high; the superradial is 4.5 mm. wide, and 1.5 

 mm. high. 



Large radials: as in C. tucanus, but side 1 is at rather less than a right angle 

 to side 6, and is at right angles to side 2. 



R' and r. ant. R' are as in C. tucanus, but no longer touch any portion of the 

 primaxil. 



The T-piece is smaller below than in previous species, and abuts less on the stem- 

 facet; the exact extent of the side-wings cannot be made ont from the specimens; the 

 width below is 1.25 mm., the height is 1.25 mm. 



Anal structures: x rests on the T-piece and probablv on the inferradials; its 

 sides abut on the primaxils of the ant. and 1. post. arms. It is followed by similar plates 

 which form a surface like that in C. tucanus, but higher, and in it portions of three plates 

 beside x are visible. The visible edges of all these plates are raised into a ridge against 

 which the maimixils abut. 



Arms: 1. ant., — only 3 ossicles are preserved in a, and those that are preserved 

 in b are covered with matrix. The arm seems, however, to have been of essentially the 

 same character as in C. tucanus, differing mainlv in the presence of a slight ridge along the 

 sides of the ossicles. IBr x , as in C. tucanus, abuts against the second alpha-brach of the 

 adjacent axil-arm, but owing to the increased smoothness and linearity of that arm this 

 does not result in the formation of an additionnl side; the ossicle is therefore six-sidcd. 

 The succeeding brachials as seen in section are enclosed outwardly by a parabolic curve 

 and ventrally by a ret : ntrant broad V-shaped groove. 



Ant. and 1. post. arms. — The primibrachs, as in C. tucanus, form a parallelogram. 

 The mainaxils are seen up to Vlax. That part of the surface of each main-axil that lies 

 between the facets is set at rather a sharp angle to that which is npturned to bear the 

 axil-arm; the coinbined interfacet snrfaces form a gentle sinnous curve, and abut closely 



K. Sv. Vet. Akad. Handl. Ba D d. 25. N:o 2. 12 



