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\ I \\ WD OLD MIMM.K DEVONIC CRINOIDS 



73 



plates of this specimen arc represented, so Ear as they arc preserved, 

 by fig. 7. It is believed that both these specimens represent abnormal 

 variations, since the absence of a single plate in one case, and 



the presence of an extra plate in the other, are the only means 

 by which they can be distinguished from thirteen normal specimens 

 with which they have been compared. 



Formation and locality. — Alpena limestone, and Upper Traverse 

 limestone: Richard Collins' quarry, Alpena, and Partridge Point, 

 near Alpena, Mich. 



Cat. No. 36,022-23 (Rominger collection), and 35,140 U. S. X. M. 



DOLATOCRINUS sp. 



A crinoid from the Hamilton of Louisville, Ky., is represented by 

 a mold of the lower portion of the interior only, but the suture lines 

 between the plates are distinctly 

 shown, and faint ridges are present r^; : =^ > 



which probably indicate the position 

 of ridges on the outer surface of the f\ 

 crinoid (see fig. 8). The specimen 

 is referred to Dolatocrinns as an ab- 

 normal individual, since a similar 

 variation occurs in an individual 

 which may, with little doubt, be re- 

 ferred to Dolatocrinns astcrias n. sp. 

 (compare fig. 7). The fine lines on 

 fig. 8 represent the faint ridges 

 above referred to. These seem to 



(y 



Fig. 8. — Dolatocrinns sp. Ar- 

 rangement of plates. 



strengthen the evidence in favor of placing the specimen with the 

 genus Dolatocrinns. It is too imperfect for specific identification. 

 Cat. Xo. 36,027 (Rominger collection) U. S. X T . M. 



DOLATOCRINUS LACUS Lyon 

 1857. Lyon, Geol. Rep't Kentucky, in, p. 482, pi. IV, figs. 2, 2a~c. 



Formation and locality. — Onondaga: Columbus and Dublin, O. 

 Hamilton: Charlestown, Ind. The type locality is in the limestone 

 bed above the " Black Slate," Louisville. Ky. 



Cat. Xo. 36,025 (Rominger collection), 43.107 and 43,109 (Ulrich 

 collection) U. S. N. M. Also in Massachusetts Institute of Tech- 

 nology, Xo. 654. 



