134 SMITHSONIAN INSTITUTION 



IBB not prominent, but visible in side view. BB large. Anal x truncate 

 or obtusely angular, scarcely higher than radials. RR very large, four or five 

 times the height of IBr ; height of B to R to IBr, 3.5 :4_5 :i. IBr variable, one 

 or two. Higher brachials and column unknown. 



Angelin thought this species had four " basalia " (infrabasals), and therefore proposed 

 for it the genus Cyrtidocrinus. This was due to incorrect observation, and his genus cannot 

 be upheld. The type specimen cannot be identified, and his figures show a peculiar surface 

 marking, as if there were depressed strips on the plates running parallel to their margins such 

 as I have seen occasionally in other species (cf. L. macro petalus, PI. Ill, figs. 8a, b) ; but this 

 was evidently much exaggerated by the artist, as it is not shown on any of Mr. Liljevall's 

 drawings. 



There are two abundant and well-marked species of Lecanocrinus in Gotland. One 

 occurs in the northern region at and near Wisby, in horizon d, and it has very thick calyx 

 walls, high, acute-angled anal x, and relatively small radials ; the other occurs at Naf dem, 

 Hablingbo, and other localities in the south of Gotland in horizon c or d, and has a thin 

 calyx, low obtuse-angled anal x, and very large radials. The first, as we have already seen, 

 is L. billingsi. The second is considered at the Riks Museum to be L. facietatus, and the form 

 of the anal plate in Angelin's figures indicates the correctness of this reference. 



Of this species there are about 120 specimens in the Riks Museum, but very few with 

 any part of the arms attached. There seems to be more irregularity in the number of primi- 

 brachs than is usual in Silurian species. Out of 12 specimens of which the IBr are preserved 

 in 26 rays, 15 rays have two IBr, and 11 have only one. The form bears considerable re- 

 semblance to L. pisiformis from Tennessee, especially in the low anal x and very large 

 radials ; but it has better developed infrabasals and a more truncate base, and differs in the 

 surface ornament — the latter a poor criterion practically because the surface is rarely well 

 preserved. It is probable that the so-called ornament which I have illustrated on Plate 

 II, figures 19^, 21c, is nothing more than the network formed by the surface growth of 

 stereom, and that this surface ought to be called smooth. 



Type. Cannot be identified ; the specimens figured herein are all in the Riks Museum, 

 Stockholm. 



Horizon and locality. Silurian, Wenlock Group, horizons c and d. Nas, Nafdem and 

 Hablingbo, Gotland. 



Lecanocrinus lindstromi n. sp. 



Plate II, figs. 22, 23 



Similar to L. facietatus as to the anal plate, but having proportionally 

 stronger IBB, thicker calyx walls, and a different style of surface ornament 

 consisting of small raised granulations similar to those of L. billingsi, but 

 coarser. Crown more elongate than in that species, the relative height to width 

 at IIBr being 1 to 1 as against 1 to 1.4; the anal plate and flat, short arms also 

 perfectly distinguish it. It has the same irregularity in number of IBr found in 

 L. facietatus, having 2 in three rays, and 1 in two rays. Maximum crown, 

 13 mm. high by 10 mm. wide at top of RR; width of column facet, 2.5 mm.; 

 height of B to R to IBr, 3 : 4 : 1 . 



This form is represented by two well-marked specimens, which come from the extreme 

 south of Gotland in a different locality from that of either of the other Gotland species. The 



