TAXOCRINIDAE 365 



( ?) Eutaxocrinus perplexus n. sp. 

 Plate XLVII, figs. iSa, b 



A large species. Crown elongate, widest about the third bifurcation, where 

 height to width is 45 mm. to 25 mm. ; calyx rather low and broadly spreading 

 with side outline convex; height to width at apex of axillary IBr, 12 mm. to 23; 

 base, 6 mm. ; giving spread of base 1 to 4. 



IBB low, pentagonal. BB large, and RR somewhat smaller. Post. B sup- 

 porting" a very large, rounded tube resembling' a ray, tapering gradually, com- 

 posed of very wide and short plates. Rays and their divisions divergent. Arms 

 long, bifurcating four or five times; reducing in size -by half at the first three 

 bifurcations and tapering gradually from there on. Surface smooth. IBr 

 wider than high, and as wide as the RR, leaving no shoulders for supporting 

 iBr. Br of higher orders shorter than wide until near the last branches. A 

 small quadrangular iBr in each area touches the basal in three out of the four 

 regular interradii, and was evidently followed by perisome, as the sides of the 

 rays above it are smooth and rounded. Column large, flush with IBB circlet, 

 narrowing very slightly from the calyx, and composed of very thin columnals, 

 without alternation for a distance of 20 mm. 



The unique specimen upon which this species is described is abnormal in several respects, 

 so that some of its essential characters are in doubt. The most perplexing of these is the 

 presence of a pentagonal plate at the base of the anal tube to the left of the posterior basal, 

 in the exact position of an obliquely located radianal. This in association with the ponderous 

 tube so strongly suggests an affinity with Gnorimocrinus, that if the specimen were normal 

 there would be no escape from referring it to that genus. The right posterior ray, however, 

 is doubled, the primibrachs being of extraordinary width and supporting two branches, each 

 of which has about the size and the same number of further bifurcations as the normal rays ; 

 the left posterior ray has three primibrachs instead of the normal two. Thus the posterior 

 side of the calyx is greatly altered, and the supposed radianal may be only a sporadic occur- 

 rence. In the general character of its anal structures, with the posterior basal truncate, and 

 anal x to some extent incorporated in the calyx by sutural connection, the specimen departs 

 from the family characters ; and it must in any event be treated as a variant with characters 

 modified by abnormal growth. In general habitus otherwise it fits as well into Eutaxocrinus 

 as into any other genus. 



In casting about for some possibly related form with which to compare it, one is naturally 

 reminded of the similar huge anal tube of E. juglandiformis, in which the structures about 

 the base of the tube are also out of the ordinary. In the relative size of basals and radials, 

 and in the presence in this form of interbrachials connecting with the basals (a feature not 

 repeated in this family until late in the Lower Carboniferous) the two species are widely 

 different. Both depart so strongly from others of this genus that it is by no means clear 

 that they should not be separated from it, but the imperfect and abnormal condition of the 

 specimens in the anal parts prevents this. The fact that the specimen under consideration is 

 derived from the same Stringocephalen-Kalk as those from the Eifel, a formation prolific 

 in singular forms, is another reason for referring it — although with much doubt — to the 

 present genus. 



Type. In the author's collection. 



Horizon and locality. Middle Devonian (Stringocephalen-Kalk) ; Verviers, Belgium. 



