584 NEW YORK STATE MUSEUM 



seems to indicate tliat their composition is similar to that found by Holm 

 and Wiman in Dictyonema ; or that there exist, besides the larger thecal 

 tubes, smaller ones which have separate apertures as in Dictyonema, and 

 that they do not empty into the thecae as in Dendrograptus. While Hall 

 described the apertures as being located alternatingly on opposite margins, 

 his somewhat diagrammatic drawing shows them in regular series. In the 

 Deep Mil material the apertures are irregularly scattered, or found disposed in 

 a manner suggestive of a long spiral distribution. 



Callograptus salteri Hall 



Plates, figures 13-15 



Callograptus salteri Hall. Canadian Organic Remains, decade 2. 1865. p.l35, 



pl.l9, fig.5-8 

 Callograptus salteri Hopkinson & Lapworth. Quar. Jour. Geol. Soc. 1875. 



31:667, pl.34:, fig.lO 

 Callograptus salteri Gurlej. Jour. Geol. 1896. 4:300 

 Callograptus salteri Roemer & Freeh. Lethaea palaeozoica, Bd 1. 1897. 



p.577 

 Callograptus salteri Ruedemann. N. Y. State Paleontol. An. Rep't. 1902. 



p.554, 555, 565 



Description. Rhabdosome infundibuliform, its outer margins forming an 

 angle of 40°-50*'. Branches springing from a thin, flexuous hydrorhiza 

 without the intervention of a coarser stem ; thin (.5 mm ad max.), numerous 

 and closely arranged, the interspaces being less than the width of the 

 branches ; iiexuous to undulating, bifurcating at irregular intervals, the 

 I'esulting branches diverging but slightly and assuming immediately sub- 

 parallel directions; rarely connected by dissepiments. Thecal apertures 

 circular, little projecting, arranged in irregular series, numbering 14 to 18 

 within 10 mm ; smaller pores observable between the larger apertures. Often 

 longitudinally striated, where the thecal tubes have been pressed through the 

 periderm. 



Position and localities. Fragments of this species are, at the Deep 

 kill, common on slabs of graptolite bed 2 (Tetragraptus horizon), but have 

 also been observed on those of graptolite beds 1 and 5. 



