46 F. A. BATHKK, CRINOIDKA OF GOTLAM). 



are all primitive i ri one respect or another. H. Ammoms unay w r ell lmvc becn derived 

 from such a form as H. convolutus. 



H. fltilitlUfirriis H. Amrnowis. 



I , I 



//. brachiatus H. t let dier i II. convolutus. 



H. scolopepidra. 



The genus is at present kriown only from Silurian rocks. 



Species of the genus. 



H. brachiatus., Hall sp. 



Cirri few, alternating, and only in region 6; they spring from the back of the 



ossiele; cirrus-ossicles longer t han wide, cylindrieal. Outcr median sutures 



elear, lateral unseen. Coil very open. 

 Niagara Group, N, America. 



Herpetocrinus Fletcheri 



(Plate I, H^s. 24—49.) 



1873. Salter, Cat. Camb. and Si]. Foss., p. 118; Cambridge. 



1878. Mtfelodactylus héterocrintes, Angklin, Iconographia j>. 11, Tab. X, figs. 24, 25. 



Diasnosis. 



Cirri irregular in regions 4 and 5, 2 to eacli ossiele in region 6 only; cirrus-ossicles 

 slightly longer than wide, moniliförm. Outer lateral sutures clear, median sutures unseen. 

 Coil farely quite close. 



The type-specimeiis of this species are in the Woodwardian Museum at Cambridge; 

 the description of them and of the other British specimens will be more suitably given in 

 an Eriglish publicätibn. Here only the Gotland specimens are treated of. 



There are in the Riksmuseum 14 specimens that may be referred to this species, 

 viz. (a), the original of Angelin's Tal). X, fig. 24, from whieh the following description 

 of the crown is for the most part taken; (b), the original of Tab. X, fig. 2ö; (c) a spe- 

 cimen with the crown in the embrace of the cirri (201 MR); ('/ and e) two iraperfect 

 specimens of stem; (/, g and K) three stem-fragments; (i) a well-preserved stem; (j) a 

 long slightly eurved stem -fragment; (k) a beautifully preserved and complcte individual 

 (lig. 36); (/, ui, it) Weathered stems. 



Description. 



Crown is 30 mm. long, but the arms are broken. 



Dorsal cup is elongate: its compositiori is not easily made out in speciraen <i, 

 sinee the härd crystalline matrix was not easily cleared away, but it can be better seen 

 in speeimen fa 



