84 LOWER PENINSULA. 



side, with the prostrate, creeping, reticulated tube portions. The 

 basal expansions of the former species, represented in the same 

 figure, do not always grow in uninterrupted leaves, as in the frag- 

 ment represented, but often in an open network like that in the 

 larger figure. In some specimens the tubules are more nearly ap- 

 proximated than they are seen to be in Fig. i. 



SYRINGOPORA TABULATA, Milne-Edwards. 



Synon., Thecostegites Bouchardi, Milne-Edwards. 



Large, convex colonies of diverging, subparallel, straight tubules, 

 forming incrustations of other marine bodies with their creeping, 

 Aulopora-like, basal ends, which subsequently continue to grow 

 in an erect position. Tubules about one millimeter wide, closely 

 approximated, with intervals narrower than a tube diameter ; the 

 transverse connecting tubules branch off in subregular, verticillate 

 position, and correspond in all tubes in certain levels, by the 

 lateral anchylosis of which almost uninterrupted laminar floors 

 are formed ; this is, however, not an invariable structure. The 

 same specimens often exhibit portions in which the trans- 

 verse branchlets are not verticillate, but in irregularly dispersed 

 position, and in which no laminar floors intersecting the colonies 

 are perceptible. The tubules are distinctly radiated by twelve 

 spinulose crests, and on the surface of the tubules a dull, longitu- 

 dinal striation is usually noticed. Diaphragms funnel-shaped, with 

 tubular invaginated ends. The floors of connecting processes are 

 in some specimens moderately distant, as in that represented 

 on Plate XXXII., upper specimen to the right. These are the 

 typical form of Milne-Edwards' Syr. tabulata. In other specimens, 

 particularly those of smaller size, forming incrustations of shells, 

 etc., these floors are in close approximation, and form a series of 

 superimposed laminae, separated by small vesiculose interstices. 

 Milne-Edwards, misapprehending their structure, described them as 

 the type form of a new genus, Thecostegites ; but a little more 

 careful examination would necessarily have shown him the specific 

 identity of his Syringopora tabulata with his Thecostegites Bou- 

 chardi, both described as occurring at the Falls of the Ohio, from 



