4 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 65. 



hasaltifonnis as figured b}^ E. Forbes.** They are in marked con- 

 trast to those of the enormous cirri of B. mexicanus^^ in which the 

 cirrus-facets fill almost the entire height of the combined nodals. 

 In none of the specimens is any portion of the cirrus itself pre- 

 served. 



The normal joint-face in nearly all the specimens is so much 

 decomposed that the details of structure are usually obliterated, but 

 as before there is fortunately one specimen in which these are well 

 preserved, showing distinctly the unmistakable characters of Bala- 

 nocrinus (figs. 10, 10a). The petaloid sectors are thoroughly well 

 marked ; the floors, or ligament fossae, are large, obtusely triangular, 

 considerably depressed, or excavate. In each sector there are about 

 10 peripheral crenellae at right angles to the periphery, with usually 

 another one at either side next to the radius not reaching the pe- 

 riphery, which according to Bather's terminology would be called 

 adradials, thus making 12 crenellae in all; they are short, those 

 which are strictly peripheral being about one-forth the length of the 

 radius, here again contrasting with those of B. mexicamts, in which 

 the length of the crenellae is from one-third to two-thirds that of 

 the radius. On the syzygial face the crenellae are shorter, but ap- 

 parently somewhat less in number (fig. 9«). In other specimens 

 the narrow radial ridges are conspicuous, straight, apparently sep- 

 arated by the radial canal, but perhaps partly confluent (figs. 

 4a, 5a). The axial canal is apparently round, and the lumen very 

 small. 



The species with which comparison is invited is the one from the 

 later middle Miocene horizon of Italy, already mentioned, Balano- 

 crinus lorioli of Noelli. It is described from three stem fragments, 

 of which two are figured, respective!}' 17 and 8 mm. in length, about 

 6 mm. in diameter, with 9 and 4 columnals about 2.5 mm. in height. 

 The columns are said to be subpentagonal, and have exteriorly some 

 longitudinal furrows, with one or more rows of small pores alternat- 

 ing with them, some of which may be exposed by weathering. Two 

 normal joint faces are figured, both obscure in details of structure. 

 According to the text each petal has 7 to 10 crenulae (denti) at the 

 periphery. The differences shown by comparison of stem fragments 

 alone are therefore of rather minor importance, not greater than 

 might be found in different parts of the same stem. However, we 

 have to make the best of such evidence as we have, considering the 

 rarity and imperfection of the specimens. 



That which does give to our species a veiy special interest is the 

 fact that its occurrence in the Miocene of the West Indies furnishes 



• Monog. Tertiary Echinod, Palacontogr. Soc, 1852, pi. 4, figs. 8, 9. 10. 

 » Proc. U. S. Nat. Mus., vol. 61, 1922, pi. 1. 



