Prof. S. A. Nicholson — New Devonian Fossils. 57 



Chaetetes monilifokmis, Nicholson. PL IV. Fig. 7, a, h. 



Spec. char. — Corallum ramose, the branches having a diameter of 

 from three to five lines. Corallites polygonal, with thin walls, for 

 the most part nearly equal in size, but having a few very small ones 

 intercalated amongst the larger ones. The surface exhibits rounded 

 eminences (" mamelons ") placed at distances apart of rather more 

 than a line, over which the calices are larger than in the intervals 

 between them. About four of the ordinary calices occupy the space 

 of one line. At each of the angles of each calice is a minute but 

 conspicuous nodular thickening, which gives a peculiar beaded ap- 

 pearance to the surface, but which is not prolonged inwards into the 

 interior of the corallite as a spine. On the contrary, well-preserved 

 specimens show that these bead-like or moniliform thickenings of 

 the angles of the calices are continued above the general surface in 

 the form of short blunt spines, which communicate to the coral a 

 roughness readily perceptible to the touch. 



Chaetetes moniliformis appears to be readily distinguished from 

 previously recorded examples of the genera Chaetetes, Monticulipora, 

 and Stenopora, by the moniliform thickenings of the angles of the 

 calices and the spiniform surface projections thence proceeding. 

 The walls of the calices (Fig. 7, h) are thin, and are themselves 

 destitute of spines or tubercles, the spines exclusively proceeding 

 from the points where the angles of contiguous calices come together. 

 Stenopora spinigera of Lonsdale carries spines, as its name implies, 

 but these are borne by the walls of the calices all round, and the 

 other characters of the fossil are different. Stenopora exilis, Dawson, 

 from the Carboniferous rocks of Nova Scotia, also possesses spines ; 

 but these likewise spring from the margins of the calices, are much 

 more numerous than in the present species, and are different in form 

 and arrangement, whilst the calices are oval instead of being poly- 

 gonal, and the entire coral is of a more slender and branching habit. 

 In addition to its peculiar spines, Chaetetes moniliformis is further 

 characterized by the comparatively large size of the calices, their thin 

 walls, their polygonal form, and (with the exception of those occupy- 

 ing the "mamelons") their nearly equal dimensions. 



Locality and Formation. — Eare in the Hamilton Shales of Widder, 

 Township of Bosanquet. 



Chaetetes Barkandi, Nicholson. PL IV. Fig. 7, c. 



Spec char. — Corallum ramose or forming small lobate masses, 

 with a diameter of from two to five lines. Corallites polygonal, thin- 

 walled, nearly equal, though with some smaller ones irregularly 

 intercalated amongst the larger ones. The surface does not exhibit 

 distinct eminences, but here and there are groups of corallites 

 slightly larger than the ordinary ones, and separated by intervals of 

 about a line and a half. From four to five calices in the space of 

 one line. 



This species (Fig. 7, c) is closely allied to C. Goldfussi, Edw. and 

 H., but is distinguished by the fact that the calices are markedly 

 polygonal, instead of being circular or oval, and that they are sub- 

 equal, with a very few smaller ones intercalated amongst them, 



