390 Mr. C. Wachsmuth on the Internal and 
In a specimen of Actinocrinus in which the digestive organ 
is apparently perfect, though showing the usual rough appear- 
ance, I succeeded in removing at one side the two upper convo- 
lutions, in such a manner that the detached parts can be re- 
placed or lifted up for investigation. J had here an opportu- 
nity to examine the inner or, more properly, upper end of the 
alimentary canal (as distinguished from the outer end or termi- 
nal part). he top is unfortunately hidden below some inor- 
ganic matter; but enough can be seen to prove that it pro- 
ceeded evidently from a place below the centre of the dome. 
The organ, where it comes into view, is an elongated tube, which, 
passing downwards, widens first gradually to near the middle 
of the visceral cavity, then rapidly until it acquires the width 
of at least two thirds of the entire length of the cavity. The 
upper end in descending spirally turns from right to left, but 
on becoming wider curves sharply in the opposite direction 
and the convolutions are now directed from left to right. The 
outer end, also tapering rapidly and forming a flattened tube, 
ascends the outside spirally from below all the way up to the 
top, and, I am inclined to suppose, proceeded tothe proboscis, 
being probably analogous to the terminal intestine of the 
Kchini, while the upper end communicated with the food- 
groove. 
Such, with slight modifications, was probably the con- 
struction of the alimentary canal of all Actinocrinide, Platy- 
crinide, &e., but not that of the genus Ollacrinus*. I found 
the alimentary canal partly preserved in Ollacrinus tubercu- 
losus, Hall, in which it seems to have been composed of the 
same delicate network ; but the organ consists here of a round 
canal which descends spirally, and, contracting gradually, takes 
at the lower portion of the visceral cavity an upward direction. 
The upper part of the organ is unfortunately not preserved in 
this specimen. 
4. The Anal Aperture and the Proboscis. 
The anus of Paleeozoic Crinoids is placed always within one 
of the interradial series, which is generally wider than, and 
often constructed differently from, the others. The aperture 
is situated either in some part of the calyx itself, or at the top 
* Figured by Cumberland without generic or specific diagnosis or spe~ 
cific name, London, 1826, in the Appendix to ‘ Reliquize Conservatee.’ 
Synon. :—Gilbertocrinus, Phillips, 1836, Geol. Yorkshire, pt. ii. p. 207. 
Goniasteroidocrinus, Lyon & Casseday, Suppl. Geol. Rep. Iowa, p. 70. 
Trematocrinus, Hall, 1860, Suppl. lowa Geol. Rept. p. 70. 
As Cumberland’s figure is perfectly correct and easily identified as Olla- 
crinus (Gilbertocrinus) calcaratus, his generic name “ Ollacrinus”’ must be 
retained according to the laws of nomenclature. 
