16 P. HERBERT CARPENTER. 



structure, as I have explained elsewhere.^ Studer refers to 

 the figure of Haplocrinus rosaceus, Roem. on p. 347 of 

 ZitteFs well-known work on Palseontology. Two species are 

 figured on this page, viz, Coccocrinus rosaceus, F. E-oera., 

 and Haplocrinus mespiliformis, Goldf., both from the 

 Devonian beds of the Eifel. Neither of them is " ungestielt," 

 as may be seen by reference to Taf. xii, in Schultze's well- 

 known ^ Monographic der Echinodermen des Eifler Kalkes,' 

 from which Zittel copied his figures ; while on pp. 89 and 105, 

 Schultze describes the stem-characters of the two species. 

 Studer's subsequent remarks indicate clearly that Haplo- 

 I crinus should read Coccocrinus, and that he is comparing 

 the disc of Ophiopyrgus with the calyx of Coccocrinus 

 rosaceus. Unfortunately, however, this species does not 

 possess a dicyclic base. For the plates which Studer calls 

 Parabasals, describing them as having assumed an actinal 

 position and supporting the orals are the primary interradials. 

 These rest on the upper angles of every two contiguous radials ; 

 whereas if they were '' parabasals " they should be situated 

 between radially placed " basals '' (which are not present) and 

 the radials themselves ; and one of the radials would rest on 

 the upper angles of every two of these plates, this being 

 exactly the reverse of their real position ! 

 \ Studer's comparisons further imply that the terminal plates 

 of the Ophiurid arm are after all the homologues of the 

 Crinoid radials ; but this is the very point which Ludwig 

 disproves in the useful memoir which Studer quotes. The 

 plates which Ludwig recognised as the radial primaries (PI. I, 

 fig. 13, 4), are considered by Studer to be the lower ring of 

 basals (under-basals of the rational nomenclature) ; this being 

 necessary to establish an homology between an Ophiurid and a 

 dicyclic Crinoid. My own attempt at an homology between 

 Ophiurids and Crinoids is of later date than the presentation 

 of Studer's memoir to the Berlin Academy, but anticipated its 

 publication by nearly sis months. As he has added no note 

 upon the subject, I conclude that he did not know of my 

 » This Journal, vol. xviii, 1878, pp. 372, 373. 



