

Absence of Basals in the Eugeniacrinidse. 329 



consisting of a u gradually expanding funnel-shaped piece, 

 which seems to be composed of coalesced upper stem-joints." 

 But the cup of B. Aldrichianus was described by him * as 

 consisting " of a series of basals which are soldered together 

 into a small ring, scarcely to be distinguish*! from the upper 

 stem-joint." 



No sutures are visible between these basals upon the exterior 

 of the calyx ; but sections of a decalcified calyx show them 

 very clearly, though they end just short of the edge, so as 

 not to appear externally. In the same way there is no trace of 

 interbasal sutures in the adult B. Carpenterif, though they 

 are visible in youn'g individuals. In all these three species, how- 

 ever, the interradial sutures are perfectly distinct ; while they 

 are always traceable in those specimens of R. lofotensis which 



I show no interbasal sutures, even in transverse sections of the 



decalcified calyx. The same contrast between the persistence 



I of the interradial and interbasal sutures has been noted by 







Palaeozoic Allagecrinus 



x 



May we not therefore consider the Eugeniacrinida3 as pre- 

 senting another instance of the total disappearance of the inter- 

 basal sutures ? Do not the analogies of Rhizocrinus and Bathy- 

 crimes, Encrinus and Allagecrinus, all point to the conclusion 

 that the so-called uppermost stem-joint of the symmetrical 

 Eugeniacrinidse really consists of five closely anchylosed" 

 basals ? 



Like the corresponding part of the calyx in Rhtzocrinus 

 and Bathycrinus, it is pierced by five interradial canals, each 

 of which forks just below the synostosis of this piece with the 

 radials above. In Encrinus, Apiocrinus, Millericrinus, Penta- 

 crinus, Metacrinus, &c, and in the larval Comatulce, each of 

 the basals is perforated by one of these bifurcating inter- 

 radial canals ; and no Crinoid is known with these canals 

 situated anywhere else but in the basals. They lodge the 

 I five primary cords which proceed outwards from the cham- 



j bered organ towards the circular commissure contained within 



1 the radial pentagon. The axial cords of the arms originate 



in this commissure, and are the channels by which motor 



• « — . _ a * till . • . "W 



uscul 



g the 



• * "Notice of new Living Crinoids belonging to the Apiocrinidze/' 

 Journ. Linn. Soc, Zool. vol. xiii. p. 50. 



t This is the llycrinm Carpenteri of Danielssen and Koren. See the 

 'NytMagazin for Naturvidenskaberne,' 23rd Bind, 1877, p. 4 (of sepa- 

 rate copy). 



% Crinoideen des Muschelkalks, pp. 43, 44. 



§ Ann. & Mag. Nat. Hist. ser. 5, vol. vii. p. 288. 



Ann. & May. N. Hist. Ser. 5. Vol. xi. 23 







