140 ANNALS NEW YORK ACADEMY OF SCIENCES 



ments quite irregular, partly thickened. Thecse 15 in 10 mm., uot much pro- 

 jecting, rarely visible. 



Note : Sometimes an old stage of var. acatlica has these characters. 



J. Hall's 13 Dictyonema irregularis resembles most this variety, but 

 has a closer arrangement of the branches (25-28 in 1 inch) and occurs 

 in higher Orclovician of Canada and Great Britain. Dictyonema liom- 

 frayi, described by T. Hopkinson and Ch. Lapworth, 14 seems to be a 

 closely related species. Desmograptus intricatus, as shown in fig- 30, p. 

 609, by Euedemann (1), exhibits exactly the same type in early stages, 

 though belonging to the Chazy and having appressed thecse. No well- 

 preserved, large specimens are known, but several pieces are found indi- 

 cating a width of the colony of more than 60 mm. 



Staurograptus dichotomus Emmons var. apertus Rued. 



(1) 1904. R. Ruedemann, pp. 612-614, pi. 2. 

 (11) 1891. G. F. Matthew, "Bryograptus Jcjerulfi," Trans. Roy. Soc. Canada, 

 Sect. IV, No. VI, p. 35. 

 1892. G. F. Matthew, "Bryograptus patens Matth.," No. VII, p. 95, figs. 

 la, Id (excl. lower figure of 16). 

 (10) 1895. G. F. Matthew, id., p. 268, pi. 48, fig. 4 (?). 



1895. G. F. Matthew, ''Bnjograptus lent us Matth.," id., p. 270, pi. 48, 



fig. 2. 

 1895*. G. F. Matthew, "Clonograptus proximatus Matth.," id., p. 265, pi. 

 48, fig. 1. 



In 1895, G. F. Matthew tried to keep separate five species of Clono- 

 graptus and Bryograptus, occurring in Division 3, band c on Navy Island, 

 N. B. In 1903, Euedemann 15 followed him, believing that four of 

 Matthew's species were again recognizable, but a year later, in his Mono- 

 graph on the Graptolites, he came to the conclusion that practically all 

 these species and even genera present only definite stages of growth and 

 preservation. of Staurograptus dichotomus, a species established by Em- 

 mons in 1855, but rather dubious up to 1904. Euedemann, indeed, 

 furnished such a description and figures of this species, especially of the 

 variety "aperta" that complete identity with the species of Matthew 

 enumerated above becomes apparent, if we look over the types of 

 Matthew, which fortunately were in part accessible to me. 



13 Canadian Organic Remains. Geol. Surv. Can., Dec. 2, p. 136, pi. 20, figs. 1, 2. 

 1868. 



14 Graptolites of the Arenlg and Llandeilo rocks of St. David's. Quart. Journ. Geol. 

 Soc. London, Vol. 31, p. 668, pi. 36, fig. 13. 1875. 



is "The Cambric Dictyonema fauna in the Slate Belt of Eastern New York." N. Y. 

 St. Pal. Ann. Rep., Bull. 69, p. 938. 



