No. 89.] 61 



This species presents no distinct serratures on the margin, which is simply 

 undulating with the extension of the processes described, which probably mark the 

 place of the serrature. It has been seen only in small individuals or fragments; 

 but its great comparative width, the rigid distant ^ 



spinules and absence of defined serratures are ^ 



distinguishing characters. 



The accompanying figure is of a fragment of "> | 



this species, twice the natural size. ^1 



Geological position and locality. In the shales 

 of the Hudson river group : Near Albany. 



The Genus Gladiolites or Rettolites of Barrande was proposed for certain 

 graptolitic forms having the general features of the biserrate Graptolites, as 

 G.pristis, G. mucronatas, and others; but the structure of the entire substance 

 of the stipe differs in being apparently minutely celluliferous or reticulate. 



GENUS GLADIOLITES = RETIOLITES (Bahrande). 



" PoLYPiER small, flat, triangular, elongate, formed of two series of symmetrical 

 cellules arranged along the axis. These cellules extend from a single internal 

 canal, which occupies the central part of the polypier: their orifices are disposed 

 upon the sides of the triangle; they make an angle with the axis, and leave no 

 spaces between them." 



** The only known species has its surface covered with a film, which appears to 

 envelope it." 



I have recognized in the Clinton group of New York a species corresponding to 

 this generic description, the M. venosus (Pal. New York, Vol. ii, pa. 40, pi. a 17, 

 f. 2), which is there described as a Graptolithus. In the Report on the Geologi- 

 cal Survey of Canada for 1857, I have described two other species. An examina- 

 tion of some specimens of another similar form from the Hudson river shales near 

 Albany (New York") has convinced me that one of these is sufficiently distinct to 

 form the type of a new genus, for which I have proposed the name Ret^ograptus, 

 from its reticulated structure, and from the absence of serratures of cellules reach- 

 ing to the axis. 



\ 

 RETOGRAPTUS BARRANDI (n. s.)- 



Stipes small, sublinear; sides essentially parrllel. Envoloping crust of the stipe 

 finely veined., somewhat thickened : the skeleton reticulate with three or more 

 rows or series of subquadrangular reticulations, without midrib or central axis: 

 no defined cellules or serratures; margins with projecting mucronate or recurved 

 spinules. 



The specimens are nearly all deprived of their outer 

 crust, leaving the skeleton alone. 



The accompanying figure is from a specimen, twice 

 enlarged. 



Geological position and locality. In the shales of tha 

 Hudson-river group : Near Albany. 



I am by no means certain that this fossil, in its perfect 

 condition, or in all its stages of growth, consists of 

 three rows of cells. The structure and mode of growth 



\^ 



