32 F. A. BATHKK, CRINPOIDEA OF GOTLAND. 



Tab. IV, tigs. 4, 4 a, 4 /> are enlarged drawings of a small ovoid form from Petes- 

 vik; the trilobate shape is not skown in 4 b, and the basals might in the same view have 

 been given a little more clearly; the posterior radial process is not distinguished in 4 a; 

 otherwise the drawings are adequate. 



Localities in Gotland: Petesvik in Hablingbo (c)"; '('anal' near Medebys in Ha- 

 blingbo (c), Qvinnegårda in Hafdhem {jicle Ang.) (c), Stenbro in Silte (c), Djupvik in Kksta 

 (c), Road between Mölner and Klinteharnn (c), Westergarn (c), Stora Carlsö (c), Lau (c), 

 Lilla, Carlsö (f), Klinteberg (f). 



Pisocrinus ollula. 



(Plate I, fi<rs. 12—19.) 

 1878. Angeltn, Iconographia, p. 21, Tab. IV, fig. 2, 2 a, 2 c, 2 d, not 2 b. 



Emended diagnosis. 



Cup bowl-shaped; height less than 2 / 3 width. Base circular; BB very small, entirely 

 covered by stem. Ant. R, r. ant. R and R' bend inwards rather sharply below, forming 

 a slight concavity, in middle of which is attached the stem. Radial processes rather stout, 

 especially in post. IR, widening towards centre of cup. 



Description. 



Dorsal cup: Angelins figures 2 and 2 a give a good idea of the general shape: 

 a single cup found near Hemse railway-station in June, 1 892, is of more conical form. 

 Si/e variable: specimens from Linde Klint are 4.5 mm. wide by 2.25 mm. high (Pl. I, 

 tig. 16), and 4.5 mm. wide by 2 mm. high (Pl. I, tig. 15), measuring to the bottom of 

 the radial facet. Specimens from the Klinteberg are 8.4 mm. wide by 3.25 mm. high (Pl. I, 

 fig. 17). A specimen from Petesvik is 6.75 mm. wide by 4.25 mm. high (Pl. I, fig. 19). 



BB 5, of unequal sizes; lie in a deep depression which is circular (Pl. I, fig. 19) 

 or slightly triangulär (Pl. I, fig. 13), and are covered by the stem. The outline of the 

 base appears to coincide with that of the proximal stem ossicle, but it is almost impossible 

 to distinguish the basi-radial sutures. -The sutures between 1. post. B and post. B, and 

 between r. post. B and r. ant. B, are so faint as only to be seen by the most careful 

 arrangement of light: the other sutures are quite clear. This fact, while it coiToborates 

 the interpretation of the Ttriacrinus basals given above, shows how slight is the limit 

 between the two genera; indced it is probable that, while some Sj)ecimens of this species 

 might be referred to TviacrinuK, there are specimens of Triuerirms with every character 

 < >f Pisocrinus. 



\l\l 5; of same general shape as in l\ pilula, l»ut the larger radials eurve round to 

 form pari of the basa! concavity. The radial processes are Ironi 1 mm. to 2 inni. high: 

 lliev are gonerallv rather broader than in 1\ pilula, and vriden into a broad spear-head: 

 their ground plan, as seen in lig. 17, has a roughlv triangulär outline, the apex being 

 truncated by the ouler wall of I lie cup, and the base being cxeavated by the ealycal 

 cavity: the posterior process is considerably wider Ihan the others (Pl. I, tig. lli). The 



