1896. 



NOTES AND COMMENTS. 



363 



two independent series of zoological exhibits, each complete in itself, 

 but the one rather richer in skins, and the other better supplied with 

 fossils. 



Uintacrinus at the British Museum. 

 We have already drawn attention to recent important acqui- 

 sitions of fossil Vertebrata, to which might be added the bones of 

 /Epyomis, collected in Madagascar by Dr. Forsyth Major, and ex- 

 hibited at the soiree of the Royal Society. Among Invertebrata new to 

 the Geological Department, the place of honour goes to a fine slab of 

 Niobrara Chalk from West Kansas, containing twenty-two crowns of 

 the free-swimming crinoid Uintacrinus. Since remains of this genus 

 were first found, twenty-six years ago, in N. America and Westphalia, 

 and described almost contemporaneously by Grinnell and Schlueter, 

 our knowledge of its structure has not greatly advanced. It has 

 presented zoologists with a puzzle for which they have attempted 



Fig. 1. Fig. 2. 



Uintacrinus socialis. Upper Cretaceous ok America, § nat. size. 



Fig. 1, from the side. Fig. 2, from below, c, centrale ; B, basals ; R, radials ; 

 IBr lt first primary brachial ; Ax, axillary brachial ; i, 2, 3, etc., secondary brachials, 

 bearing/, pinnules, some of which are included in the walls of the cup, viz., f.p. The 

 intercalated plates, which bind these elements together, are shaded. 



many solutions. The large cup, with numerous plates intercalated 

 between the radii, suggested to them that Uintacrinus was a straggler 

 from the host of what used to be known as the tessellate crinoids of 

 the Palaeozoic era, and while a few connected it with the Rhodo- 

 crinidae, the majority, among whom is Von Zittel in the " Palaeonto- 

 logie" reviewed in our last number, referred it to the Ichthyocrinoidea. 

 Its want of a stalk, and perhaps its occurrence in precisely the same 

 zone as Marsupites, have caused many to ally it with that similarly 

 puzzling crinoid. 



The British Museum specimens were carefully investigated by 



2 d 2 



