106 F. A. BATIIER, CRINOIDEA OF GOTLAND. 







a 





a 





c 





d. 



Cup. 



Height 



4.0 



mm. 



3.5 



mm. 



4.0 



mm. 



3.5 mm 





Width at base... 



1.75 



» 



1.4 



» 



2.0 



» 



1.75 » 



IBB. 



Height.... 



. 1.5 



» 



1.25 



» 



1.5 



» 



1.1 





Width above 



1.25 



» 



1.0 



» 



1.0 



» 



1.0 » 



BB. 



Height 



1.75 



» 



l.G 



» 



2.o? 



» 



2.0 » 





Width above 



. 1.4 



» 



1.25 



» 



1.5? 



» 



1.5 » 



RR. 



Height. 



1.6 



» 



1.75 



» 



1.75 



» 



1.25 » 





Width above 



. 1.75 



» 



1.8 



» 



1.8 



» 



1.75 » 





Width of facet.. 



1.25 



» 



1.2 



» 



? 



» 



1.25 » 



RR widen very slightly, and then slope in gently to the facet, which is directed 

 upwards and very slightly outwards. 



R' is small and quadrangular, not square; the sides next r. post. R and r. post. B 

 are curved. The side abutting on post. B is 1 mm. long, that abutting on r. post. B is 

 0.85 mm. long: the measurements are from speeimen a. 



Anal structures: Anal x, as seen in speeimen a, is 1 mm. high and is sunk 

 rather below the level of the radials. As usual in the genus, it supports two plates. 



Ventral tube: The two plates resting on x are followed by hexagonal plates in 

 longitudinal series, of which three rows are seen abreast in speeimen a, four rows in 

 speeimen c. The plates are broader than high and exhibit no sign of folding, and cer- 

 tainly none of pores or slits. The tube can only be traced to a length of 5 mm. in 

 speeimen a; but in speeimen c, where all is seen, it is 1 1 mm. long, and appears to widen 

 above into a large sac, a feature also noted in H. proboscidialis. 



The Arms dichotomise quite regularly, the ossicles regularly lessening in width at 

 each dichotomy. The ossicles have smoothly rounded backs and are very slightly nionili- 

 form. The primibrachs are 1 mm. high and 1 mm. wide; the secundibrachs are a little 

 longer than wide. Tlie following are the numbers of the series as observed: 



a. Ii. c. d. 



IBr... 4, 4, 4 6? 4, 4 5, 5. 



IIBr 5, 4, 4, 5, 4 6? 5, 4?, 5, 4 unknown. 



IIIBr 4?+, 4?+ unknown 6,7,5+ » 



The arms would appear from speeimen c to have reached a length of 18 mm. at least. 

 Their ventral surface is not very distinct. 



The Stem is subpentagonal proximally, and more round distally. It is composed of 

 high and low ossicles regularly alternating. The width of the stem is about 1.2 mm.; 

 the higher ossicles are about 0.5 mm. high and in the distal region are slightly swollen. 

 The sutures between the ossicles are slightly crenelate. The length of the portion of stem 

 preserved in one speeimen is 15 mm., in anothér it is 30 mm. The longest stem frag- 

 ment on this shib that can with safety be referred to this species is 70 mm. long. 



This species bears some resemblanee in details, as well as in general appearance, to 

 Angelin's Tab. X, lig. 28, named Myelodactylus gracilis. Ilad the name gracilis^ not 



