224 - • SMITHSONIAN INSTITUTION 



axillary IBr, followed by three plates abreast, and two or more ranges above. 



iBr one nearly as large as the anal, followed by others of irregular size, many 



of them isolated by surrounding perisome which becomes continuous above, 



passing into the tegmen; illBr areas similarly constructed, and perisomic plates 



also occupy the axils of lower ramules. RR the largest plates in the calyx, being 



both higher and wider than iBr. IBr 3, exceptionally two. Rays long, each 



ramus bearing five or more long ramules only from inside of dichotom; these are 



heavy, unequal, branching three or four times also from inside at intervals of 



3 to 4 brachials, not diminishing regularly, but the first one smaller than the 



next. Column large, about flush with the infrabasal ring; composed from the 



calyx down of projecting columnals alternating with shorter and narrower 



ossicles, without any enlargement in upper part. 



Types. All in the Riks Museum, Stockholm. 



Horizon and locality. Silurian, Wenlock Group, horizon /; Wisby, Island of Gotland. 



