61G NEW YORK STATE MUSEUM 



colony, wlien seen in a vertically compressed condition [fig.8-10]. The 

 cross of branches stood vertically on the axis of the sicula or had a 

 horizontal position in the snspended rhabdosome as is illustrated by figures 7 

 and 17. (5) The four branches of the second order form at once neAV 

 bifurcations. One of them lies usually a little closer to the center [fig.9-11] 

 than the others, thus often giving to the colony the appearance of having pos- 

 sessed a six rayed center [fig.l2-14j. The stage with the four branches 

 of the second order and the eight branches of the third is that 

 which Emmons figured and employed to base his S. dichotomus on. 

 (6) The later branches bifurcate irregularly and apparently, as in Clono- 

 graptus, without limitation. (7) The laterall}' compressed specimens 

 [fig.17-21] show that the branches at the beginning grew in a nearly 

 horizontal direction [fig.17,19], but later on turned obliquely downward, the 

 whole rhabdosome thus forming an inverted broad, low cone [fig.20,21] with 

 an apical angle of 110°- 120°. 



Memarhs. Where the initial branching is not very distinct, a criterion 

 by which the last mentioned laterally compressed forms could be distin- 

 guished from species of Bryograptus is lacking; and without the presence of 

 the other flat mode of preservation and the growth stages they could hardly 

 help being considered as belonging to that genus. It is evidently for these 

 reasons that Matthew [1895] has described two species of Bryograptus as 

 associates of the species under discussion, which, from the extensive material 

 collected at Schaghticoke, 1 believe to be other modes of preservation of 

 S . dichotomus. In a preliminary paper on the Dictyonema 

 flabelliforme beds in New York [1903, p.938] the writer has also listed 

 these species of Bryograptus which he at first thought to be well distin- 

 guished from Staurograptus. 



While, however, the Bryograptuslike mode of preservation is by far 

 the rarer — as is also stated by Matthe^v — both the normal Staurograptus 

 and the Bryogi'aptus form have been noticed in the same specimen, one 

 part of which had been flattened vertically and another compressed laterally. 

 This supports the suggestion of Elles [1898, p.532] that "great variation 



