SYSTEMATIC PART. 157 
Fistulata. The former embrace the families Haplocrinidx, Pisocrinide, 
Symbathocrinide, and Cupressocrinide ; the latter the Hybocrinide, Hetero- 
crinide, Anomalocrinidse, Belemnocrinidx, Gasterocomide, Catillocrinide, 
and Calceocrinide of monocyclic forms, and the Dendrocrinide, Cyathocri- 
nid, Poteriocrinidze, Astylocrinid, Encrinide, and Pentacrinidas among 
dicyclic forms. The arrangement is substantially the same as that proposed 
by us in 1885, in Part III. of the Revision, except that we withdraw the 
Gasterocomide from the Larviformia, and place them among the Fistulata. 
This change was announced by us in 1890,* when we restricted the Larvi- 
formia to those Inadunata in which the orals rest against the radials, and the 
ventral surface is covered exclusively by the orals, 2. e. Crinoids which 
remain persistently in the larval state. 
A different division of the Inadunata has been lately proposed by Mr. 
Bather,f who subdivided the Inadunata into “ Monocyclica” and “ Dicye- 
lica;”’ but whether they should be ranked as suborders, he leaves as yet in 
doubt. In alluding to the Larviformia and Fistulata, Bather says these divi- 
sions “cannot well be maintained. Many genera hitherto included in the 
Larviformia have quite as good a ventral sac as some acknowledged Fistu- 
’ 
lata.” We do not know of any group to which this remark can be applied, 
unless Mr. Bather undertakes to homologize the narrow anal tube of Synbatho- 
erinus and Pisocrinus with the ventral sac of the Fistulata. Symbathocrinus 
has no ventral sac, but simply an anal tube, nor has it an anal plate, or 
perisomic pieces as we once supposed; its asymmetrical oral pyramid rests 
directly upon the radials, and its anal tube is supported by the radials and 
orals together. Bather further says: “they (W. and Sp.) excluded /etero- 
crinus and Calceocrinus, in which it has at all events never been proved 
that other plates beside orals occur in the tegmen.’ We supposed it was 
now admitted that the ventral sac represents morphologically the highly 
developed posterior inter-palmar area of the disk, as was proved by the 
position of the anus, which is situated either at the anterior side of the sac, 
or not within the sac at all, but in front of it (toward the oral centre) in the 
main part of the tegmen. Admitting this, the presence of the sac proves 
that the Heterocrinide had a complicated disk. 
The case is very similar in the Calceocrinide and Catillocrinide. Both 
agree with the Larviformia in having no anal plate, at least no anal x; but 
* Proceed. Acad. Nat. Sci. Phila., 1891, p. 355. 
t The Crinoidea of Gotland, Part L., with ten plates (Stockholm, 1893), p. 20. 
