]881.] NATURAL SCIENCES OF PHILADELPHIA. 297 



1878. Melocr. Volborthi Angelin. Iconogr. Crin. Suec, p. 20, PI. 7, figs. 8-11, and 

 PI. 23, figs. 30-32. Upper Silur. Gothland, Sweden. 

 (Angelin figures under this name at least two difierent species, his PI. 18, fig. 

 16, represents even another genus ; the latter possibly goes together with the 

 specimen on PI. 26, fig. 26, referred to Patelliocr. fulminatns.) 



10. SCYPHOCKINUS Zenker. 



1833. Zenker. Beitr. Naturgesch . d. Urwald., p. 36. 



1839. Miinster. Beitr. z. Petrefactenk ., iii, p. 112. 



1850. Quenstedt. Handbuch der Petrefactenk,, p. 621. 



1855. F. Roemer. Letbaea Geogn. (Ausg. 3), p. 255. 



1878. Zittel. Haudbucb der Palaeontologie, i, p. 372. 



(Not ScypTiocrinus Hall, 1847. Paleont. N. York, i, p. 85.) 

 (Not Scyphocrinus Pictet, 1857. Traite de Paleont., iv, p. 320.) 



The genus under consideration is not to be confounded with 

 Scyphocrinus Hall, 1847, which is an entirely different thing, and 

 as we believe, a synon^-ni of Schizocrinus Hall. Scyp/iocrinus 

 Zenker, is imperfectly known, but Zittel is probably correct in 

 grouping it with Melocrinus, although it has in the form of its 

 radials, and in the large number of interiadial plates, close 

 affinities with Feriechocrinus , from which it differs in the 

 construction of the anal area. Pictet's identification of Scypho- 

 crinus is evidently not correct ; he describes it with four under 

 basals and five basals, arranged like in Cyathocrinus^ and 

 otherwise resembling Actinocrinus. 



Generic Diagnosis. — Calyx very large, composed of numerous 

 thin plates, which are beautifullj^ sculptured ; posterior side some- 

 what wider, and hence the general symmetry slightly bilateral. 



Basals, according to Roemer and others-, five. Zittel gives their 

 number at four. Primary radials 3X5, nearly of equal size and 

 varying but little in form, all higher than wide ; the two lower 

 hexagonal ; the third heptagonal and supporting two rows of 

 secondary radials, each consisting of from four to five plates, 

 longitudinall}' arranged and separated by interaxillary pieces. 

 The radials support ten arm-trunks, which give off' numerous' 

 branches, the latter closely placed together, the lower ones crossing 

 each other and forming in the interradial and interaxillary spaces 

 an unbroken pavement ; higher up, however, the arms become free 

 and diverge, giving off long slender branches, which ixi turn 

 throw off pinnule-like armlets (Zittel), but probably true pin- 

 nules. The main trunks and branches consist of short single 

 joints with deep ventral furrows, their articulating faces provided 

 with radiating strife. 



