MELOCRINID^. 267 



subdivisions with reference to it^ calling those in which some trace of anal 

 plates is found Melocrinites, and those in which they are completely absent 

 in the cup Dolatocrinites. We find it impossible to make these divisions 

 families, because they seem very intimately related in other respects, and 

 shade into each other too closely, — both forms being possibly represented 

 in species of the same genus. This is probably the case in Hadrocrinus ; 

 while in AUocrinus the first interbrachial of the posterior side is somewhat 

 larger than the corresponding plate of the other sides. 



The name Melocrinidge was introduced by Roemer.* It was applied by 

 him, and afterwards by Angelin,t Zittel4 and S. A. Miller,§ exclusively to 

 genera with four basals, or those that were supposed to have four. Gl^pto- 

 crinus, with five basals, although closely allied to Mariacrimis and Melocrinus, 

 was referred by Zittel, and S. A. Miller, who substantially adopted Zittel's 

 classification, to the Glyptocrinidae under which they included a variety of 

 genera, both monocyclic and dicyclic. In the classification of 1890, Miller || 

 refers to the Glyptocrinidae Cu/pulocrinus, Glyptocrimis, Pi/cnocrinus, ScJiizo- 

 crinus, and Siphonocrinus — the first an Ichthyocrinoid ; SipJionocrimcs — a 

 Thysanocrinoid — and both of these last dicyclic. This is the more curious 

 because Miller is the author of Siphonocrinus, which he described as having 

 three infrabasals ; while he emphatically denied the presence of infrabasals 

 in Gh/ptocrinus ; and yet in establishing the families of the Crinoidea 

 made the '^presence or absence of ' subradials'" next in importance "to the 

 number of basals," upon which his classification is principally based. 



I. MELOCRINITES. 



Symmetry of the dorsal cup disturbed by one or more anal plates. 



GLYPTOCRINUS Hall. 



1847. Hall; Palfeont. New York, Vol.^ I., p. 280. 



1854. McCoy; Synops. Brit. Palaeoz. Eoss., p. 56, 



1856. Billings; Canad. Naturalist and Geologist, No. 1., p. 49. 



1857. Billings; Geol. Surv. Canada of 1853 to 1856, p. 256. 

 1859. Billings; ibid., Decade IV., p. 55. 



1873. Meek ; Geol. Surv. Ohio, Pal^ont., Vol. I., p. 30. 



1874. S. A. Miller; Cincin. Quart. Journ. Sci., p. 348. 

 1879. Zittel; Handb. der Palaont., Vol. I., p. 375. 



* Lethgea Geogn., 1855 (Ausg. 3), p. 228. 



f Iconogr. Crin. Suecise, p. 19. 



% Handb. der Palseontologie, Vol. I., pp. 368-375. 



§ Amer. Palseoz. Possils (second edit.), p. 276. 



11 American Geologist, Vol. IV., pp. 275 to 286, and pp. 340 to 857. 



