TAXOCRINIDAE 35 1 



Stockholm. Looking at the angular inner margin of the left posterior ray in a specimen like 

 that of figure 14a, Plate XLV, it would seem contrary to the rule we have stated for the 

 structure of the anal side in the Taxocrinidae ; but it is evident from that and other figures 

 that these marginal angularities were not for sutural attachment of solid plates, but were 

 merely ornamental. The spaces opposite them are actually occupied by perisome which is 

 attached at the inner margin of the plates ; and the same angularities are seen on the higher 

 brachials where neither interbrachials nor perisome are present. 



The ornament on the brachials in the form of disconnected longitudinal ridges or 

 wrinkles is quite distinct for the species. Angelin's figures were made from two specimens, 

 from both of which I give new and more detailed figures. Two other fragments have fur- 

 nished fine enlarged drawings of the interbrachial spaces (PI. XLV, figs. 15, 16) ; in the 

 first may be seen some of the coiled arms toward the distal end, showing how extremely 

 slender they become. 



Types. In the Riks Museum, Stockholm, Sweden. 



Horizon and locality. Silurian, Wenlock Group (horizon /) ; Follingbo, Island of 

 Gotland. 



Protaxocrinus ovalis (Angelin) 



Plate XLV I, figs. 8-n 



Taxocrinus ovalis Angelin, Icon. Crin. Sueciae, 1878, p. 8, pi. 20, figs. 13, 14. 



Taxocrinus (Gnorimocrinus) ovalis, Wachsmuth and Springer, Revision Palaeocrinoidea, pt. 1, 1879, 



Protaxocrinus ovalis, Springer, Jour. Geology, XIV, 1906, p. 515. 



Type of the genus. 



A small species, similar to P. interbrachiatus and perhaps only the young 

 of that species; agreeing with it closely except in the shorter, wider habitus, 

 better definition of iBr plates, and the absence of ornament on the arms. In that 

 case however, the former species would become the synonym, and P. ovalis 

 would stand, being the first on the page of Angelin's descriptions. In the preser- 

 vation in which these fossils are often found the absence of such ornament may 

 be misleading. A maximum specimen gives the following proportions : height 

 to width of crown, 1.7 to 1; calyx to top of IAx, 1 to 1.7; spread of calyx, 

 1 to 2.2. Height, 17 mm. ; width, 10 mm. ; base, 4 mm. The first interbrachial 

 plate is relatively larger in these specimens, but the development of perisome 

 is entirely like that of P. interbrachiatus. 



Types. Riks Museum, Stockholm, Sweden. 



Horizon and locality. Silurian, Wenlock Group (horizon /) ; Follingbo and Sigdes, 

 Island of Gotland. 



