BY F. RATTE, ING. DES ARTS ET MANUF., PAEtlS. 1077 



such an aberrant genus as it was supposed to be. It is closely 

 allied to Cromyocrinus and Agassizocrinus, and like them has large 

 basals, comparatively small radials, and an unusually large azygous 

 plate, followed by the anal piece and proximate plate of the ventral 

 tube. It differs, however, from both genera in the number of 

 underbasals, and the peculiarities in the radial regions which have 

 been mentioned." 



And of the genus Cromyocrinus (1) they say : " Cromyocrinus is 

 closely allied to Agassizocrinus, to which it holds a similar 

 position as Pentacrinus to Antedon. We doubt if Cromyocrinus 

 ever became detached from its column, while all species of 

 Agassizocrinus lose their column comparatively early." 



In harmony with the above lines the authors say further in 

 their diagnosis of T r ibrachiocrinus " Column apparently small and 

 circular." 



In fine, according to these authors, our fossil is placed in the 

 family Poteriocrinitke which, in the subdivision Fistulata of the 

 sub-order Inadunata, comes next to Cyathocrinidce, and is followed 

 by Encrinidcz. 



Before ending this note I must add to the description of 

 Tribrachiocrinus corrugatus a detail which is supported by a 

 closer examination of the original, namely that the ridges are 

 provided along their summits with a line of small tubercles, and 

 that the isolated tubercles support ordinarily a smaller tubercle at 

 their summits. 



(1) Part III. Sect. 2, p. 171. 



