128 ' P. H. CARPENTER ON TWO NEW CRICOIDS FROM 



10. On two new Ceinoids from the Uppee Chalk of Southern 

 Sweden. By P. Herbert Carpenter, Esq., M.A., Assistant 

 Master at Eton College. Communicated by Prof. P. Martin 

 Duncan, M.B. Lond., E.K.S., F.GKS. (Kead February 2, 1881.) 



[Plate VI.] 



The large work * of Prof. Geinitz on the fossils from the valley of 

 the Elbe in Saxony contains a description of a small stalked Crinoid 

 from the " Planerkalk " of Strehlen that has long been known to 

 contain stem-joints of the type to which d'Orbigny gave the name 

 Bourgueticrinust. Although no calyx was ever met with, the 

 characteristic stem-joints were supposed to be sufficiently indi- 

 cative of the presence of the common B. ellipticus. Some ten years 

 ago, however, a singularly perfect specimen was discovered, con- 

 sisting of a complete stem with radicular cirrhi, and a calyx 

 on the top of it (PI. VI. fig. 1). But this calyx (fig. 2) proved 

 to be totally different in its characters from those of the species 

 of Bourgueticrinus described by d'Orbigny. In B. ellipticus the 

 calyx is widest round the basal circlet, and tapers gradually 

 downwards into the stem, while the outer surface of the radials 

 has a considerable slant from above downwards and outwards. In 

 d'Orbigny's other species, B. cequalis, both radials and basals, 

 especially the latter, are relatively narrower and higher, and the 

 whole calyx, together with the top stem-joint, is almost uniformly 

 cylindrical ; but in each case the top stem-joint is very large and 

 relatively higher than that of any Apiocrinus, while in B. ellipticus 

 it widens considerably from below upwards. Its height may be as 

 much as or more than that of the basal and radial circlets together ; 

 and the joints immediately below it gradually diminish in width 

 until they resemble the ordinary stem-joints. 



In the Strehlen fossil J, however, the calyx is widest at its upper 

 end, around the upper and outer edges of the radials, so that its 

 diameter diminishes gradually from above downwards (PI. YI. 

 fig. 2a). The broad external faces of the radials slope downwards 

 and inwards ; and the basal circlet narrows still more, so that the 

 diameter of its lower face is less than two thirds that of the upper 

 surface of the radials (fig. 26). But the top stem-joint, on which the 

 calyx rests, only expands a little from its lower to its upper margin, 

 and its increase in thickness over the one below it is far less marked 



* " Das Elbthalgebirge in Sachsen," Palseontographica, Baud xx. Theil 2, 

 pp. 18, 19. 



t Histoire naturelle generate et particuliere des Crinoides vivans et fossiles 

 (Paris, 1840), pp. 95, 96. 



| Thanks to the kindness of Prof. Geinitz, who has made a second exami- 

 nation of this specimen, I am enabled to give a slightly more accurate figure 

 of it than that published by him in the 'Elbthalgebirge' (Taf. vi. fig. 9a). 

 In the older figure only two joints are represented between the calyx and the 

 enlargement on the stem. In that given here three joints are shown instead of 

 two, this later interpretation of the markings on the upper part of the stem 

 being considered by Prof. Geinitz to be the more accurate one. 



