142 PROCEEDINGS OF THE ACADEMY OF 



regard the latter group as a section or subgenus under the old name Taxocrinus. 

 In this sense, then, we leave under the names Forbesiocrinus, our F. Monroensis 

 and T. Nonvoodi, as well as all those mentioned in the foregoing list from No. 

 12 to 22 inclusive. Our FJ semiovatus, however, seems to be a typical Taxo- 

 crinus, and its name should be written Taxocrinus semiovatus. The species 

 Forbesiocrinus nun tins, F. Thiemei, F. communis, F. Kellogi, F. spinifer, and F. 

 juvenis, of Hall, we regard as likewise typical forms of Taxocrinus, and hence 

 their names should be written Taxocrinus nuntius, T. theimei, T. communis, T. 

 Kellogi, T. spinifer, and T. juvenis. 



Taxocrinus gracilis, Meek and Worthen. 



Body small, expanding moderately from the base. Basal pieces small, and 

 looking like the last joint of the column divided into three pieces ; subradial 

 pieces so small and narrow as to allow the lower middle extremity of the 

 first radials to come nearly, or in some instances, quite down upon the basal 

 pieces ; four of them triangular and more or less wedge-shaped so as to pro- 

 ject up between the first radials as much as half the length of the latter ; the 

 fifth one larger than the others, but slightly tapering, and truncated above by 

 the anal? piece, so as to present a quadrangular or subpentagonal outline. 

 First radial pieces considerably larger than the subradial, of nearly equal 

 length and breadth, or a little wider than long, hexagonal in form, the infe- 

 rior sloping, and upper horizontal sides much longer than the others. Se- 

 cond radials, in four of the rays, shorter than the first, wider than long, and 

 generally hexagonal ; in the fifth ray of the specimen under investigation, 

 the second piece has its right margin enormously, and perhaps abnormally, 

 developed, and extended obliquely upwards, so as to fill the whole interra- 

 dial space above the comparatively minute interradial piece, quite up as far 

 as the second bifurcation of the rays, with one solid plate. In the ray con- 

 taining this singularly developed second piece, there are two other primary 

 radial pieces succeeding it, of near the natural size and form, upon the last 

 (fourth) one of which the first bifurcation takes place ; after this each of the 

 divisions bifurcates again on the fourth piece, and the two inner subdivi- 

 sions again on the fourth piece, while the two outer ones send off" subdivi- 

 sions, one on the sixth, and one on the seventh piece. In the ray immedi- 

 ately to the right of that just described, and apparently the anterior one, no 

 division takes place until upon the eighth piece, all the pieces between the se- 

 cond and eighth being transversely oblong or about twice as wide as long, and 

 gradually diminishing in size. In the other three rays, the first division 

 takes place on the third piece, and the second and third divisions also on the 

 third piece, the arms rather rapidly diminishing in size with each bifurca- 

 tion. 



Interradial pieces very small, rather longer than wide, somewhat wedge- 

 shaped above, and resting between the short superior lateral sloping sides of 

 the first radials, and supporting on each superior sloping side a short trun- 

 cated margin of the contiguous second radials, which generally meet over the 

 little interradial, so as to isolate it from the free space above, though not 

 always. Anal piece a little larger than the interradials hexagonal in form, 

 and resting with one short side upon a truncated upper side of the largest 

 subradial ; while it connects on the right with a first and second primary 

 radial, and on the left with a second and third primary radial, and one first 

 secondary radial. 



Surface of body apparently smooth, but showing granules on some of the 

 divisions of arms. Patelliform accessory pieces not developed between the 

 primary radial pieces, but quite distinct between some of the secondary. 

 Column, as in other species of the group, round and tapering downwards 

 from the base, near which it is composed of very thin pieces. 



This species, although somewhat like T. intemcapularis, Hall, (Iowa Report, 



[Aug. 



