122 LOWER PENINSULA. 



DIPHYPHYLLUM RUGOSUM, Milne-Edwards. 



Eridopiiyllum RUGOSUM, Milnc-Edwards. 



Of very similar sructurc to the former, but its stems are smaller, 

 less than one centimeter in thickness ; the gemmation from the 

 calyces is very prolific ; from four to six gemmae grow at once from 

 an end cup ; the stems are tortuous, geniculated, annulated by 

 sub-regularly repeating constrictions, and by delicate linear striae of 

 growth ; the lateral processes, for mutual attachment of the stems, 

 are acanthiform, quite numerous. Calyces forming rounded, 

 moderately deep excavations with slanting sides and erect margins. 

 Lamellae crenulated, from forty to fifty in the circumference of a 

 calyx, and extending nearly to its centre, which is generally formed 

 by a very narrow diaphragm, not transgressed by the lamellae, but 

 not separated from the outer area by an internal wall. 



This species is not found in Michigan, but is a very common form 

 in the Niagara group of Indiana and Kentucky, and because of its 

 close affinity to the former species, I have considered it of interest 

 to describe and represent it in this place. 



Plate XLV. — Fig. 2 gives a side view of a silicified specimen from 

 the vicinity of Louisville ; the stems are of somewhat larger size 

 than the specimens usually have. 



DIPHYPHYLLUM MULTICAULE, Hall. 



Syringopora multicaulis, Hall. 



Flexuose cylindrical stems, from three to four millimeters in di- 

 ameter, distant from each other about one tube diameter, connected 

 by narrow, remote spurs resembling the transverse tubules of a 

 Syringopora. Surface faintly ribbed by septal striae, and encircled 

 by wrinkles of growth. Calyces deep, with almost vertically erect 

 walls, radiated by about thirty crenulated lamellae, of which half the 

 number are marginal ; the others reach to the centre. Interstitial 

 spaces filled with vesiculose plates. Diaphragms generally obscured 

 by frequent intersection with the lamellae ; more rarely the central 



