Fi«;, 
Fig!' 
Fig-; 
PLATE CXV. 
Tubicolar Annelida op the Hudson Eiver Group Cornulites ; in various 
. STAGES OF DEVELOPMENT. 
Pages 8-18. 
A portion of the surface of a much macerated Orthoceras, showing the earliest stages of growth 
' observed. 
The same specimen, enlarged to three diametei-s, the relative distances between the tubes being 
diminished in the drawing. The tubes show every variation in form, from the completely en¬ 
rolled helicoidal condition, suggestive of Spirorhis, to the partially enrolled or serpuloid stage* 
and to the more elongate, sinuous foi-m characteristic of Cor?mlites. The Spirm-bls Cincinnati- 
ehsis, Miller and Dyer, pi-obably represents the earliest or coiled condition of these bodies In 
the smallest examples here illustrated the surface is entirely smooth, but with advancing 
growth becomes first faintly and then more strongly annulated. The largest of the specimens 
also show faint longitudinal striae. In these latter tubes the embryonal tips have been broken off. 
' Hudson River group. Cincinnati, Ohio. 
Tubes in about the same condition of growth as those described in the preceding specimen, en¬ 
larged to three diameters, showing the distinct transverse annulations. The tubes are all 
attached for their entire length to a valve of Strepto rhynchusplano-convexus. This is ths stage 
of develo]unent represented by the species Ortonia minor, Nicholson. 
Hudson River group. Cincinnati, OWw. 
A fragment of Monticulipm’a, bearing numerous tubes in the Serpuloid condition represented in 
fig. a. Each of these tubes is finely but distinctly annulated, but the longitudinal striae are but 
pai-tially developed. Enlarged to three diameters. 
Hudson River group. Cincininati, Ohio. 
A single, slightly flexuous tube, natural size, with strong, somewhat irregular annulations and 
very fine longitudinal striae. This is' the condition of growth reitresented by the species 
Tentaculites Sterlingensis of Meek and Worthen. 
Hudson River gi-oup. Cincinnati, Ohio. 
The same stage of growth exhibited by thi-ee tubes attached to one another and, at their bases, to 
a fragment of a crinoidal stem. 
The same, enlarged to three diameters, showing the longitudinal striae. 
Hudson River group. Cincinnati, Ohio. 
Thi-ee tubes of somewhat larger size and more flexuous form, attached to a crinoidal [fragment. 
These specimens show an inci-easing irregularity in the annulations. 
Hudson River group. Cincinnati, Ohio. 
An isolated group of similar tubes, attached to one another for their entii-e length and growing upon 
the fragment of a crinoidal column. ' Natural size. 
The opposite side of the same specimen. 
Hudson River group. Cincinnati, Ohio. 
A gi-oup of adnascent tubes attached to a valve of StrophomeTia atto'nata. 
Hudson River group. Cmcinnati, Ohio. 
Two larger tubes attached to a single crinoidal segment. In this form the annulations have be¬ 
come more irregular and obsolescent, and the longitudinal sti-iai much more conspicuous. 
Hudson River grou}!. Cincinnati, Ohio. 
Two adnascent tubes in which the annulations are extremely irregular, and have become 
obsolescent. 
Hudson River group. Cincinnati, Ohio. 
A group of smallei- tubes, showing the increasing irregularity and obsolescence of the annulations. 
Hudson River group. CindnJiati, Ohio. 
A large tube, having a surface of similar character to that repi-esented in the last three figures. 
Enlarged to two diameters. 
A longitudinal section through the same specimen, showing the dense cellular wall and the folds 
on the internal surface, coi-responding to the external annulations. 
Hudson River group. Cincinnati, Ohio. 
A group of simple tubes in a very early stage of development, having a common point of attach¬ 
ment and a radiating habit of growth. 
Hudson River gi-oup. Cmcinnati, Ohio. 
The under or basal side of a silicified specimen, aflbrding a more perfect illustration of this mode 
of growth. The outer walls of the tubes where shown are distinctly annulated. 
The upper surface .of the same specimen, showing the apertures of the’ connate tubes, the entire 
colony presenting a strikingly favositoid appearance. 
The view represented in fig. 8, enlarged to three diameters. 
Hudson River gi-oup. Cincinnati, Ohio. 
Basal view of a similar specimen, in a somewhat more advanced stage of growth, showing the 
point of attachment and the annulated surfaces of the tubes. 
The uj)per surface of the same specimen. 
The same, enlai-ged to thi-ee diameters, showing the apertures and concenti-ically annulated inter¬ 
nal surface of the tubes. 
Hudson River group. Cincinnati, Ohio. 
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Fig. 21. 
FiS. 22. 
Fig. 23. 
