258 CATALOGUE OF THE BLASTOIDEA. 



Oropliocrinus verus are totally unlike one another in general appearance (PI. V. 

 fig. 26 ; PI. XL fig. 5 ; PI. XIII. fig. 3 ; PL XV. fig. 1) ; but they all agree in having 

 a tolerably high basal cup, and also in the general characters of the hydrospires. 

 The slits are excavated either wholly or partially in the substance of the calyx-plates, 

 and are not simply the upper openings of lamellar tubes, which are more or less 

 independent of these plates as in other Blastoids (PI. V. fig. 5 ; PI. X. figs. 12-14 ; 

 PL XVI. fig. 20). In Codaster and Phcenoschisma some or all of the slits are 

 permanently open at the sides of the ambulacra (PL XL figs. 1-6 ; PL XII. 

 figs. 1-6 ; PL XIII. figs. 1, 4, 6, 8 ; PL XIV. figs. 1-12). But in Cryptoschisma 

 (PL V. figs. 23, 24) the ambulacra are so wide that they entirely conceal the hydro- 

 spire-slits, a condition which is almost reached in Phcenoschisma caryophyllatum 

 (PI. XIV. fig. 3). The slits are partly visible in some species of Oropliocrinus 

 (PL XIV. figs. 15, IS), but in the more typical species they are rather more closely 

 approximated and grouped together near the bottom of the radial sinus, where they 

 are overlapped by the linear ambulacra and so concealed from view (PL XV. figs. 4, 

 10 ; PL XVII. figs. 12-14). In this genus, too, the deltoids appear on the exterior 

 of the calyx above the radial limbs (PL XIV. figs. 14-18 ; PL XV. figs. 1, 6), which 

 is not the case in either Codaster, Phcenoschisma, or Cryptoschisma. These facts 

 enable us to divide the Codasteridse into two subfamilies Phsenoschismidse and 

 Cryptoschismidse, the first of which is very well defined, but the second less so. 



Both are represented in the Lower Devonian of Spain ; while the former occurs 

 in America as well, each genus passing up into the Carboniferous Limestone on both 

 sides of the Atlantic. Of the Cryptoschismidae, however, one genus is limited to the 

 Spanish Devonian, and the other to the Carboniferous of Britain, Belgium, and 

 America. 



(i.) Subfamily Ph^noschismid^e, E. & C, 1886. 



Definition. Eight or ten groups of hydrospire-slits, which are partially or entirely 

 visible. Deltoids limited to the summit, not appearing externally. 



lit marks. The characters of this subfamily are so well shown in our figures on 

 Pis. XT. -XIV. that we need say but little about it. Apart from the direct communi- 

 cation of the hydrospires with the exterior, it is chiefly distinguished by the position 

 of the radio-deltoid suture, which starts from the distal end of the oral crest and cuts 

 the hydrospire-slits more or less directly at right angles (PL XL figs. 3, 5, 6 ; 

 PL XIII. figs. 1, 4, 8). Phcenoschisma, like most other regular Blastoids, has hydro- 

 spires in the anal interradius ; but these are absent in Codaster (PL XII. figs. 1, 4, 

 8 ; PL XIII. figs. 1, 4, 7), which is thus as sharply defined a genus as Elceacrinus is. 

 Its relations to Phcenoscliisma are shown in the following table : — 



