2 12 NEW YORK STATE MUSEUM 



The specimens here referred to are preserved in an extremely fine- 

 grained, greenish gray shale in which the jet-black branches of the grapto- 

 lites become very distinct by color contrast. To these branches are attached 

 in great number brown elongate triangular appendages [see pi. i i, fig. 1-4] 

 which clearly were conical in shape originally. Their lighter color is obvi- 

 ously due to greater thinness of the perisark and from the fashion in which 

 the black branches are at their broken ends continued into brown shreds of 

 like brown color, it would appear that the conical bodies are formed by but 

 one or few of the perisarcal layers. They exhibit distinct transverse lines 

 of the appearance of growth lines [see pi. 11, fig. 2] and a very sharp dark 

 outline except at the distal margin where the supposed aperture is situated. 

 The proximal end is distinctly contracted into a narrow tube with thicker 

 wall. This in the best preserved specimens possesses two opposite lateral 

 notches for the insertion of smaller conical bodies which sometimes are also 

 preserved [pi. 11, fig. 4], consist of like brown substance and bear like 

 growth lines. The larger conical bodies were in such numbers attached 

 to the branches that in some places [pi. 11, fig. 1 at a] the)* form closely 

 arranged series. From the great number of such bodies found loose on the 

 Covington slabs and the fact that they are missing altogether on the numer- 

 ous large rhabdosomes from the shales at Holland Patent, it is to be inferred 

 that they were very easily detached and lost. 1 The explanation for this is 

 found in their extremely small base of attachment and the probable pres- 

 ence of a joint at the latter; for not only do they always detach at this 

 point, but it is also quite evident that the basal tubes were attached directly 

 over the pores observable in the branches from which the appendages have 

 been stripped, and that the walls of these pores do not appear rough, but 

 smooth. 



What are these conical appendages ? 



'A typical specimen of M. tenuiramosus from the black Lorraine shale at 

 St Bruno Mountain, Co. Chambly, Quebec, sent to. the writer for identification by Profes- 

 sor Whiteaves, showed at first glance no trace of these bodies, but a smallei oranch could 

 be uncovered which retained them in a line state of preservation. 



