314 Mr. F. A. Bather on British Fossil Crinoids. 



Palmars = Brachials of the third order. -P. II. C. (MS.). 



Postpalmars=: Brachials of the fourth order. 



Free brachials= u the component pieces of the arms heyond the last axil- 

 lary."— P. H. C. (MS.). 



Si/zi/c/u. " Only used for the immovable (?) union between two brachials, 

 in which the h\ pozygal loses its pinnule (supposing pinnules to occur). 

 The apposed faces may be smooth (some Pentacrini), striated (most 

 Comatulce), or dotted (some Actinometrce)^ — P. II. 0. (MS.). 



Close Suture. " The apposed surfaces smooth or partially striated. Ex. 

 All the subradial plates, both laterally and longitudinally ; the calyx- 

 plates of most Camerata, some Platycrinidaj excepted." — P. H. C. 

 (MS.). 



Loose Suture. " Distinguished by the formation of a more or less developed 

 facet, cut out of the edge of the plate. It may be smooth, striated, 

 or have faint ridges, and is sometimes perforate. Ex. The union 

 between radials and costals of some Platycrinidse. The brachials of 

 the Camerata, Cyathocrinidse, and some Poteriocrinidae. The radials 

 and interradials of the Articulata. Stem-ossicles. Pinnule-ossicles 

 of many Neocrinoids."— P. H. C. (MS.). 



Muscular Articulation. " The articular ridge, whether vertical or trans- 

 verse, is always perforate. Ex. The brachials in all Articulata, and 

 in some Poteriocrinidae and Encrinidse (unisonal arms only)."' — 

 P. H. C. (MS.). 



Instead of the terms here given, Dr. Carpenter proposes to 

 use •' Synarthrosis " for Close Suture, " Amphiarthrosis " for 

 Loose Suture, and " Diarthrosis " for Muscular Articulation. 

 But it is very doubtful whether the adoption of terms from 

 Vertebrate anatomy is wise, especially when, as in this case, 

 the terms connote certain relations of bone, cartilage, and 

 synovial membrane, tissues that do not exist in the Crinoidea. 

 I shall therefore use the equivalents with which Dr. Carpen- 

 ter has fortunately favoured me. 



As any other of the old terms used by me will be used in 

 the accepted sense it is unnecessary here to explain them ; 

 any new terms that may seem necessary will be defined as 

 they are introduced. It is, however, important to explain the 

 orientation adopted. Any attempt at a purely morphological 

 orientation is impossible so long as homologies with other 

 Echinodermata remain uncertain. For practical purposes it 

 is best to consider the adult Crinoid in its natural position, 

 i. e. with the ventral disk uppermost, and then to view it 

 from the anal side. The anal interradius will then be Pos- 

 terior, the radius opposite to it will be Anterior, Left and 

 Right will correspond with the left and right of the observer. 

 Viewed from above, with the anterior radius away from the 

 observer, Right and Left remain the same. To preserve this 

 orientation when the dorsal cup is viewed from below, the 

 anterior radius must be nearest to the observer. The accom- 

 panying Table compares this with the various systems of 

 nomenclature that are in use ; I give LoveVs ' without 



