432 SMITHSONIAN INSTITUTION 



crinoids he had already described, together with a number of other species for which he had 

 prepared descriptions which were never published. This project was interrupted by the 

 Civil War, in which he served with distinction as an able officer, and after it was over his 

 wounds and failing health prevented him from resuming the work. When in after years 

 I acquired his collection from his family, these drawings were courteously turned over to me 

 by his son, Mr. Victor W. Lyon, of Jeffersonville, Indiana, and I have much pleasure in 

 publishing now his original figures of the two species of Onychocrinus. These show the 

 excellent character of the work at that early day, which, while published under the joint 

 names of himself and Casseday, was actually for the most part done by Lyon alone. 



Figures i, 2 of Plate LXIX are Lyon's original drawings of 0. exsculptus, — figure .2 

 from a specimen in his collection, and figure 1 from another belonging to some one else, of 

 which he had a plaster cast ; its location is unknown. These specimens were from Craw- 

 fordsville, and with them in his collection were several others from the same locality, includ- 

 ing the original of his figure 3 ; but although the description gives as one locality Clear 

 Creek, Hardin County, Kentucky, there was not in his collection any specimen of this species 

 definitely so labeled, or which was not recognizable as unquestionably from Crawf ordsville ; 

 and I have not seen a specimen of it in any of the other collections made from Kentucky. 

 Nevertheless it is highly probable that Lyon's statement of locality is correct, as 0. ramu- 

 losus, the other Crawfordsville species, is represented by authentic specimens from Hardin 

 County, and the present species has been found in the typical Keokuk of the Mississippi 

 region. 



Meek and Worthen in i860 described under Forbesiocrinus ? norwoodi an imperfect 

 specimen from the Keokuk limestone at Nauvoo, Illinois, and another in 1861 (1862), 

 Forbesiocrinus monroensis, from the Keokuk of Monroe County. Both were later rede- 

 scribed and figured side by side in volume 2, Geology of Illinois, where O. norwoodi is by 

 mistake stated to be from Monroe County also. It is plain that these specimens, which I 

 figure on Plate LXIX, figures 7, 9, represent the young and mature stages of the present 

 species. This is confirmed by the appearance of a third much better specimen in the Cox 

 collection, found near Keokuk, Iowa (fig. 8), which has all the proportions and general 

 characteristics of the Crawfordsville specimens. 



As showing how little this group was then understood, Meek and Worthen in describ- 

 ing their F. monroensis, which has the anal tube finely preserved, were much perplexed by 

 its appearance, describing the tube as a " false arm, arising directly from the summit of the. 

 upper truncate side of the largest subradial. It seems even to be inserted into a sinus in 

 the upper side of the subradial, yet one can scarcely believe it is anything but .one of the 

 smaller divisions of the arms, accidentally broken off and placed in that position." And they 

 said the anal pieces were unknown. In the revised descriptions of 1866 they referred both 

 species to Onychocrinus, and correctly interpreted the anal side in 0. monroensis, which 

 they found to be the chief means of distinction from Forbesiocrinus. They also admitted 

 that 0. norwoodi was probably identical with 0. exsculptus; and the only differences they 

 could point out between it and 0. monroensis were its larger size, and "having the two 

 divisions of each ray, after they divide in the last primary radial, continued on for some 

 distance closely united instead of abruptly diverging." This latter, as my figures on Plate 

 LXIX show, is a difference due solely to the growth of the individual. This, I think, 

 effectually settles the status of these two species as synonymous, and leaves us with the three 

 clearly valid species from the Keokuk formation. 



Types. Author's collection. 



Horizon and locality. Lower Carboniferous, Keokuk group ; Crawfordsville, Indiana ; 

 Keokuk, Iowa ; Nauvoo, and Monroe County, Illinois. 



