112 Mr. F. A. Batlicr on the 



Several specimens were distributed by Barraiide under tlie 

 manuscript name, Echinoencrinites multiramus. The present 

 authors phice it in or near the Taxocrinidfe of Angelin, 

 which is as much as to say that it belongs to the Flexibilia 

 Imj)innata. It is of interest as being older tlian any Flexible 

 genus hitiierto known, and the interest is enhanced when we 

 see how its structure accords with its age in the eyes of the 

 evolutionist (Fig. 5). The Flexibilia Impinnata of the 

 Silurian rocks fall into four main groups, wliich may pro- 

 visionally be regarded as families and named Ichthyocrinidse, 

 Taxocrinidse, Calpiocrinidte, and Sagenocrinidaj. The two 

 latter are clearly more specialized than the two former and 

 have a larger proportion of representatives in later rocks. 

 Both Ichthyocrinida3 and Taxocrinidre have isotomous arms, 

 which may abut, and in some Ichthyocrinidai even interlock, 

 by their sides. Taxocrinida3 have a iew interbrachials, of 

 which the proximal is tiie largest ; their anals form a well- 

 defined vertical series resting on the posterior basal. The 

 Ichthyocrinidfe have no interbrachials, and their simplest 

 genus, IcJithyocrinuSj has no anals. Now Caleidocrinus 

 resembles Ichthyocrinus in the absence of anals from the radial 

 circlet and in the isotomy of its arms, wliich are, as in tiiat 

 genus, sometimes im-olled at their distal ends; but it re- 

 sembles the Taxocrinidce in the presence of interbrachials 

 with occasional intei.secunJibrachs, which, however, are all 

 very small and irregular. The authors believe themselves 

 able to distinguish an anal interradius by the presence of 

 3 vertical rows of interbrachials instead of 2. But since 

 these interbrachials lay in a flexible integument, a greater or 

 less expansion of the arms would of itself expose more or 

 fewer interbrachials. However this may be, we have in 

 Caleidocrinus a genus that approaches the common ancestor 

 oi Ichthyocrinus and Ta<rocr^?^M5, although an important point 

 of divergence, and one by no means primitive, lies in the 

 minuteness of the basals. All the specimens except one are 

 assigned to C. multiramus^ which has two priniibrachs. The 

 remaining specimen, having 3 priniibrachs, Is made another 

 species, C. Barrandei. The authors' argument is not without 

 force, but " the possibility that more abundant material of the 

 two species may disclose yet other distinctive characters " 

 seems to me far from the probability. 



We return to the consideration of those members of the 

 third fauna wliich are referred either with doubt or certainty 

 to genera previously known. The first is called Calpiocrinus? 

 bohemiciis, ov sometimes Caljyiocrinus??? hoheinicus (Fig. 6). 

 The latter mode of expression is preferable, for, as the authors 



