218 Mr. F. A. Bather on British Fossil Crinoids : 



readily tliaii the EngHsli specimens, the angle with the hori- 

 zontal varies between 35° and 85°. 



The average measurements of the Gotland specimens are 

 consideraLly greater than those of the English specimens, but 

 no other difFerence is obvious. 



In such very well-preserved specimens as E 6003 (PI. XIII. 

 fig. 12) a fine shagreen ornament is seen on the cup-plates ; 

 this, however, is usually worn away, and it may be doubted, 

 from the smoothness of some otherwise perfect specimens, e.g. 

 E 1450, whether it was always present in life. In the fossils 

 its place is occasionally taken by a rough surface, that 

 presents much the same appearance to the naked eye, but 

 which consists of irregular })its rather than elevations 

 (PI. XIII. tig. 7). This roughness appears to be caused by 

 weathering along the lines of the original intimate structure 

 of the plates. A specimen of this species, so weathered, was 

 named by Angelin C. alutaceus. 



The Arms dichotomize regularly, and lessen in thickness 

 quite gradually, remaining rather stout even to their extre- 

 mities. The ossicles are rounded and slightly swollen, and 

 often might be described as moniliform, whence, no doubt, 

 Salter's MS. names of C. monile and C. nodulosus ; some- 

 times, however, they are more even in thickness. In the 

 proximal region of the arms the brachials are roughly circular 

 in transverse section, but become more laterally compressed 

 in the distal region (zincotype, p. 211, fig. 4), The axial 

 canal is very distinct and is situated just about the uiiddle of 

 the ossicle. The ventral groove is a broad, curved, shallow 

 depression (PI. XIII. fig. 10 b). In the young specimen 

 (zincotype, fig. 5 o) the axial canal is not yet separated by 

 stereom from the ventral groove, even in the primibrachs. 

 The covering-plates are long, thick, and conical both in out- 

 line and longitudinal section (PI. Xlll. tigs. 10 (i, 10 c, and 

 zincotype, fig. 4). They interlock, and run from two to three 

 and a half to each brachial. They are sometimes rather tlat 

 and narrow, with parallel sides, at other times more rounded 

 and conical ; the former variety is shown in the top left- 

 hand corner of PI. XIII. fig. 2. 



I Br from 3 to 5. When there are 3 then I Br^ is gene- 

 rally twice as high as 1 B\\ ; when there are 4 then I Bio and 

 I Brg are usually much higher than the rest ; when there are 

 5 they arc all more of a size. Three is by far the commonest 

 number. The number of I Br ma_y vary in the several arms 

 of an individual, but is generally the same. 



II Br from 2 to 4. As witli I Br, 3 is the usual number, 

 and II Bro is often higher than II Bii. 



