BY F. RATTE, ING. DES ARTS ET MANUF., PARIS. 1073 



two rings, underbasals, thus discontinuing the term subradials 

 altogether." (1) 



It is scarcely necessary to add that the arrangement of the plates 

 and their symmetry will be fully understood, provided that the 

 radials should be propeily traced. If in a fossil crinoid we know 

 the basals, we will say that the radials are "all the plates of the 

 body above the basals, radially situated," (2) or in other words 

 we will say that the radials are those plates not in contact with 

 the stem which are situated in vertical line below the arm plates 

 which determine the radiating figure of the animal. 



In my description of Tribrachiocrinus corrugatus (3), I used 

 terms previously adopted by different authors on crinoids, which 

 are not only in discordance with the new terminology, (4) but are 

 henceforth misleading. Therefore I beg leave to rectify them here. 



At page 1160 I have given a schematic table of the arrangement 

 of the different parts composing the outer structure of the 

 calyx. In that table I used letters and signs to represent these 

 different parts, as well as on plate 68. Therefore in perusing this 

 table, together with the following corresponding terms, one will 

 be enabled to understand the revised diagnosis of the genus as 

 given by Wachsmuth and Springer. (5) 



At page 1160 (Proc. Linn. Soc. Yol. IX. Part 4.) 



Instead of : Bead: 



Basal pieces Underbasals 



Sub-radial plates or First Costals Basals 



First anal plate or Intercostal Azygous plate 



Interradials or Interscapular, CD, EA. Radials 

 Interradials : (B. t AB.) Anal (the lower in the dia- 



gram pi. 68) 

 Second anal Plate of ventral tube 



Second Radials (marked at bottom Brachials (three over the 



of table by the sign t) Radials BC, DE. and 



A. t AB.) and two pro- 

 bably ankylosed brachials 

 over the Radials CD, 

 and EA. 



(1) Revision, Part I. p. 244. 



(2) Revision, Part I. page 250. 



(3) Proc. Linn. Soc. N.S.W. Vol. IX. part IV., page 1158. 



(4) Revision, Part I. p. 249. 



(5) Revision Part III. Sect. 2, p. 175. 



