CARBONIFEROUS FOSSILS OF IRELAND. 49 



Tliis species resembles the S. ruffosa, Phil., in the arrangement of the transverse ridges, but differs in being 

 much less wide in jsroportiou to the length. Length eight lines, width one inch two lines. 



Sanguinolites discoes. il/'Coj/. (PI. Vin. fig. 4). 



S/i. C/i. — Transversely oblong, convex, three times as wide as long; beaks prominent, small; anterior side 

 short, rounded ; front margin slightly convex ; posterior end oblicpicly truncated, posterior slope separated from 

 the body of the shell by a strong ridge from the beak to the posterior inferior angle ; body of the shell marked by 

 strong, transverse, equal ridges, which stop suddenly at the oblique posterior ridge, leaving the posterior slope 

 smooth. 



This shell derives its most prominent character from the discordance which exists between the posterior 

 slope and the body of the shell, the former being perfectly smooth, while the whole of the latter is strongly 

 sulcated transversely ; it is rather more depressed than the allied species. Length foiu- lines, width one inch. 



Sanguinolites Iridinoides. M'Coij. (PI. XII. fig 1). 



Sp. Ch. — Shell flat, nearly four times wider than long; anterior side short, angular at the hinge; anterior 

 side and body of the shell marked with fine, crowded wrinkles, which change into broad, obsolete undulations, 

 in passing over the obscurely marked, diagonal ridge which runs from the beak to the inferior posterior angle ; 

 posterior end broader than the anterior, obliquely subtruncate; hinge-line three-fourths the width of the shell. 



This shell resembles an Iridina in form. There is a slight depression parallel to, and a little below the 

 hinge-line ; the oblique, posterior ridge is much better marked in some specimens than in others ; above it the 

 undulations of the surface are broad, and slightly convex, but, immediately below it, suddenly diminish in size 

 and increase in number, and, becoming more prominent, continue so to the anterior end ; the depth of the shell 

 gradually increases from the anterior to the posterior extremity. From the beak to the ventral margin, mea- 

 sured at right angles with the hinge-line, one inch three lines ; from the anterior to the posterior end five inches. 

 This shell is distinguished from the S. undata, Portk., by that species having numerous, strong, prominent 

 ridges, continued without any sensible increase in number or diminution in size across the body of the shell, the 

 anterior side is also much narrower and rounded. The differences from the S. transversa, Portk., are pointed 

 out under that head. 



Sanguinolites liratus. Phil. sp. 



Sanguinolaria lirata. Phil. Pal. Foss. 

 Only very imperfect specimens of this species have occurred. The form resembles that of S. plicatits, 

 M'Coy, but the sm-face is regularly marked with strong, nearly equal, elevated ridges, parallel with the margin. 



Sanguinolites plicatus. M'Coy. (PI. X. fig. 3, a, b). 



Sanguinolaria plicata. Portk. Geol. Eep. 

 Sp. Ch. — Twice and a half as wide as long, convex ; posterior end subtruncate ; anterior end rounded ; 

 surface with close, irregular, transverse sulci, parallel to the margin. 



This species, when in shale, is usually depressed, and the transverse sulci assume the appearance of plaits, 

 or folds ; when in limestone, however, it is more convex, and the transverse markings appear finer and more re- 

 gular ; there is some indication of a diagonal keel near the beak, but it becomes obsolete before reaching half-way 

 to the posterior end ; there often appears, particularly in shale specn.iens, a concave space from the beak to the 

 opposite part of the front margin. Length seven lines, width one inch four lines. The plate containing the figure 

 of this species, under the name Sanguinolaria plicata, was presented to the Geological Society of Dublin, some 

 years ago, at an evening meeting, at which Captain Portlock was present. As he has figured the same fossil, 

 under the same name, in his Geological Report, I am uncertain whether he intended to attribute the species to 

 himself or to me. 



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