14 CALAMOCEINUS DIOMED-E. 



The interbasal sutures are distinct in one of the specimens ; in another, 

 they could easily be traced, and became prominent on the application of a 

 little potash. In another fragment of a calyx the vertical sutures of the 

 basals were completely anchylosed, and their lines could not be detected 

 either from the inside or the outside of the basal ring (Plate XIX. Figs. 

 1-3). The basiradial sutural lines were, however, always distinct, and did 

 not become anchylo.sed with those of the basals into a solid cup, as is 

 frequently the case in Rhizocrinus. These anchylosed basals were origi- 

 nally described by Sars as forming a calyciform upper stem joint. Its 

 composite structure was first traced by Pourtales, and subsequently by 

 Carpenter. The anchylosis of the basals is very similar to that of the 

 basals in Bathycrinus, but the proportionate height of the solid ring to 

 the radials is greater in Calamocrinus than in Bathycrinus, where, as 

 Carpenter says, there are no sutures visible externally. The radials ot 

 Bathj'crinus are much less closely united ; they are thin plates in con- 

 tact with one another by quite narrow sides, often anchylosed. In 

 Atocrinus of McCoy the basals and lower radials are completely anchy- 

 losed, the radial adjoining the anchylosed cup being an axillary. 



As in Hyocrinus, the first brachials of Calamocrinus are narrower than 

 the primary radials, but their mode of articulation to these, in a ridge 

 extending along the middle of the radials to a prominent projection on the 

 upper face of the radial, is very different. The mode of articulation of 

 the arms to the radials in Calamocrinus recalls that of such palaeozoic 

 genera as Hexacrinus, Platycrinus, Pisocrinus, and Cyathocrinus, in which 

 the brachials are also narrower than the radials. 



The basal ring of the imperfect specimen figured on Plate XIX. Fig. 1, is 

 completely anchylosed, and the lines of sutures can only be traced from 

 the interior (Plate XIX. Fig. 3) before the removal of the radiating axial 

 cords from the central part of the ring. The sutures are still indicated by 

 the presence of interarticular ligaments occupying the reticulation adjoining 

 the interbasal sutures. On the outer surface (Plate XIX. Fig, 1) the posi- 

 tion of the interbasal sutures is only traced with the greatest difficulty, 

 and no actual line of suture is visible. The grooves in which the radi- 

 ating cords run on the inner faces of the basals are irregularly massed 

 in groups of five, as is shown in the inner view of the basal ring (Plate 

 XIX. Fig. 2) after the removal of the chambered organ and the radial 

 prolongations of the axial cord (Plate XIX. Fig. 5). The indistinct course 



