II 



DOLATOCRINUS MARSHI, LyOD. 



Plate 1, Fig. 8, showing the abrupt bending of the first radials 

 into a pentagonal funnel shaped cavity. 



This species was described and illustrated, by Lyon, in 1869, in 

 the Transactions of the American Philosophical Society, vol. XIII, 

 p. 461, pi. XXVII, Figs, n, nl and n2. His description and 

 illustrations are very good, and for the purpose of identifying the 

 species none other are necessary, but that publication is rare and 

 but few western people ever have an opportunity to see it, and, 

 for that reason alone, we are justified in redescribing it. But our 

 principal object, in calling attention to it, is for the purpose of 

 redescribing and showing a basal view, as we have a specimen 

 hollow on the inside and showing both the exterior and interior 

 of all the plates. 



Lyon described the calyx as "discoid, with five broad, sharp 

 carina, which rise perpendicularly from the margin of the basal 

 pit, and extend outward, equally elevated to the center of the 

 third radials, the carina rising gradually from the margins of the 

 radials, then more rapidly to the center of the pieces. At the 

 center of the third radials the carina sends out branches, not quite 

 so bold as the main stem, but strong, involving all the pieces of 

 the superradials up to the arm bases. Arm bases prominent, in 

 groups of two to each ray, producing a lobed, pentagonal figure 

 of that section of the body. The dome is subcorneal; twice as 

 high as the body below the arms; surmounted by a thick, strong, 

 subcentral proboscis. The interradial fields unite to the dome- 

 covering between the arms." 



The characters above described, to which special attention may 

 be directed, are the low calyx, high vault, subcentral proboscis 

 and carina. Instead of ordinary radial ridges occupying the cen- 

 tral part of the radial plates, the whole plates are involved in 

 forming a high central ridge, in each series, which Lyon calls the 

 "carina." And they "rise perpendicularly from the margin of the 

 basal point," which is a striking peculiarity, much more notice- 

 able in a specimen than it is in his illustration or in ours, though 

 the attention of the artist was called specially to it, and our figure 

 is accurate except in giving a full idea of the height of the "carina" 



