Note on Botryocrinus pinnulatus. 



193 



Arms are preserved to a length of 85 millirn. ; tliey probably 

 readied at least 00 niillim. Thus they were more than ten 

 times the height of the cup, and this suggests that the arms 

 of the type specimen were longer than was thought. The 

 arms agree in essential structure with the type specimen, but 

 throw some light on the peculia- 

 rities of branching described for 

 that specimen. The axial canal 

 exists as a mere tongue from the 

 ventral groove in all the arm- 

 ossicles, in which respect this 

 specimen appears to differ from 

 the type, if the appearances pre- 

 sented by that specimen were 

 correctly interpreted, "i'lie cover- 

 ing-plates are numerous and 

 minute, and appear to be slightly 

 irregular in arrangement. 



I Br, in the two arms seen, 

 number 4 and 7, and avei-age 3 

 millim. in both height and width. 



II Brg is axillary and gives off 

 on its outer side a long armlet. 

 The widths of the main arm- 

 branch and the armlet, at the 

 point where the latter originates, 

 are respectively 2'5 and 1*5 

 millim. ; in other words, the arm- 

 let is § the width of the main 

 branch. The length of the armlet 

 appears almost to equal that of 

 the main branch, and it a])pears 

 to have borne smaller branches 

 or pinnules. (Fig. 3.) 



The structure just described pj^ 3 _p^rt of Anterior Arm of 

 suggests that some at least of Mr. Madeley's specimen of 

 the secondary arm-branches in ~ ' 



the type specimen are not ab- 

 normal after all, but that the 

 species does normally branch, 

 in some or all of its arms, on 

 lIBrg. In this respect, then, 



B. pinnulatus would resemble those American species oh" 

 Barycrinus to which allusion was made {loc. cit. p. 405), 

 differing from them, however, inthe facts that there may be 

 four arms to a ray, not merely three, and that the anterior 



Botryocrinus jn/inulatxs ; 

 showint? the secondary 

 branching, and indications of 

 the pinnules; very slightly 

 diagrammatized. (x2diam.) 



