REPORT OF THE STATE PALEONTOLOGIST 1901 581 



lids, that the funicle is destitute of cellules, is, hence, correct 

 only in so far as the denticulations or the apertural parts of the 

 thecae are only distinct in young specimens and noticeable only 

 at the points of bifurcation, but not along the funicle itself. 



As to the group of Dichograptidae, represented by the genera 

 Temnograptus, Schizograptus, Ctenograptus, Holograptus, Rou- 

 villigraptus and Trochograptus Holm has noted the presence 

 of a theca on each side of the sicula in the funicle of T r o c h - 

 ograptus diffusus. Concerning the structure of the 

 funicle in general that keen observer states: 1 



On these grounds, and in consideration of the many-branched 

 Dichograptidae being embedded in shale, and therefore showing 

 the thecae of the central part of the polypary only in very excep- 

 tional favorable cases, and as these thecae are analogous to 

 those in Didymograptus and other forms which are better ex- 

 posed, I draw the conclusion that the funicle in many cases, if 

 not always, was furnished with thecae. 



This conclusion is fully verified as to Goniograptus and Coen- 

 ograptus (fig. 13) by the writer's material. It becomes appar- 

 ent from these observations that the funicle does not differ in 

 structure from any other part of the stem; and probably in all 

 Dichograptidae consisted of two thecae. 



2 The four principal stems of Goniograptus are composed of 

 thecae, each internode between two bifurcations consisting of one 

 theca. For this reason all these internodes are of uniform 

 length, and, because the angle of divergence of the budding 

 thecae is constant throughout, the angles of bifurcation are all 

 alike. 



The next related genus, Clonograptus, which develops the 

 greatest number of branches and is most irregular in the 

 ^extent of its branching, has been considered, on account 

 of these characters and its earlier appearance, the progeni- 

 tor of a part of the multiramose dichograptids. It is a well 

 known character of this genus that the internodes between 

 the bifurcations not only grow to extreme length, but also 



x Geol. mag. 1895. 4th ser. 2:484. 



