78 I&s, £2) GUILE 
wards and proximalwards. An exactly similar but differently-shaped append- 
age is constant in C. caelatus from Nevada, and probably it is equally 
constant in C. phyllophorus, though here the longer, more slender virgula is 
more frequently broken. This appendage appears to differ from that found 
in such species as Diflograpsts vesiculosus Nich., in being accurately bilater- 
ally symmetrical, and in being plainly traversed by and not forming (as 
apparently is the case in D. vesiculosus) a dilatation of the virgula. 
DIPLOGRAPSIS McCoy, 1850. 
Ann. and Mag. Nat. Hist., VI., pp. 270-2. Type. D. Arestis Hisinger. 
Diplograpsis stenosus Gurley, sp. nov. 
Polypary long and very slender, when complete probably measuring in 
the majority of cases about 50™”" or somewhat more; breadth 1 to 1.5™™, the 
latter figure being rarely exceeded. Polypary very gradually widening from 
near its distal (‘proximal’) end. Sicula and extreme distal (‘‘proximal”’) 
end of polypary unknown. Virgula usually obscure, frequently invisible, 
apparently not distally prolonged. Thecz about 20 in 25™”, straight, free 
for one-half of their length, inclined to virgula 25° to 30°; apertural margin 
probably perpendicular to virgula. 
Horizon and locality.—Upper Décellograpsus zone, Magog, Canada. 
No other species of the genus possesses a polypary so slender in propor- 
tion to its length. In this respect (only in this, however) it approaches most 
nearly some Upper Silurian species, notably D. zamariscus Nich., and D. 
longissimus Kurck. 
GLOSSOGRAPSUS EMMONS, 1856. 
American Geology, I., Part II., p. 108. Type G. cz/zatus Emmons. 
Glossograpsus arthracanthus Gurley, sp. nov. 
(Diplograpsus ciliatus Emmons, 1856, Am. Geol., I., Part II., pp. 1o5- 
Toon PlateweEcasros) 
“Straight, thin and ciliated; cilia, bulbous and jointed or transversely 
marked, proceeding from the point of each serration; serrations unequal, the 
intervening smaller serrations rounded, the larger prolonged and run into the 
base of the ciliz, axis distinct. 
“The specimen is imperfect, but probably, from the character of the 
column, it was free. The entire width of the column embracing the extended 
lateral ciliz is one-fourth of an inch, the membrane is rather less than one- 
eighth of an inch wide, the margins appear to be dissimilar. In another 
specimen the end is rounded and complete, and furnished like the sides with 
ciliz. Found in Augusta county, Virginia.” 
This form is apparently a Glossograpsus. The name cz/zatuws having been 
previously used (by Emmons, and in the same paper) for a Glossograpsus, the 
name arthracanthus is proposed for this form to clear synonymy. The dupli- 
