266 PALAEONTOLOGY OF OHIO. 



lar crusts, with a slightly cupped center, from which the cells radiate in 

 every direction. Lastly, examples are not uncommon which appear to 

 have the form of small branching stems. Some of these, certainly, are 

 merely constituted by thin crusts growing upon various ramose species 

 of Chsetetes. Others, however, appear to be entirely composed of the 

 Polyzoon itself, without the intervention of any foreign body ; and it is 

 possible that these will eventually prove to be a distinct species. 



Position and locality : Cincinnati group, Cincinnati. The specimens described are 

 from the cabinet of Mr. U. P. James. 



Genus ALECTO. Lamouroux, 1821. 

 Alecto feondosa, James. 



Plate 25, figs. 3, 36. 



Aulopora frondosa, James ; named, but not figured or described, in the Catalogue of 

 Lower Silurian Fossils of the Cincinnati group, 1871. 



Polyzoary creeping, adnata, of reticulating and anastomosing branches, 

 which sometimes become more or less completely confluent, and thus 

 :give rise to a thin expanded crust, or which may be partially reticulated 

 and partially confluent. When the branches form a network, the 

 meshes are usually extremely variable in size and disposition, but they 

 are in general more or less oval, and have a long diameter of from half a 

 line to a line or more. The cells are uniserial on the narrowest branches, 

 but biserial, triserial, or multiserial on other parts of the coenoecium ; 

 • elongated and tabular, immersed below, but free towards their aperture, 

 the terminal portion of the tube being more or less elevated above the 

 general surface. Cells from six to eight in the space of one line. Cell- 

 mouths terminal, circular, of the same diameter as the tube. 



There does not appear to be any reason for doubting that this is a true 

 Alecto. It is nearly allied to A. auloporoides, especially as regards the size 

 and form of the cells ; but the greater width of the branches, and their 



■ common coalescence into crusts, together with the greater number of the 

 rows of cells over most parts of the coenoecium, communicate to the fossil 

 quite a peculiar appearance, and appear to be characters of specific 

 value. The above description is drawn from type specimens kindly fur- 

 nished by Mr. U. P. James. The examples that I have seen are parasitic 

 upon the valves of Orthis and Strophomena, and upon various species of 



■ Chsetetes. 



