PALEONTOLOGIC CONTRIBUTIONS 1 5 



unwarranted, in the absence of distinctive sponge characters, he, on 

 the other hand, suggests (p. 270) that certain of the organisms 

 generally though doubtfully ranged with the graptolites might be 

 more at home among the algae, pointing to the similarity in the 

 texture of the Kokomo forms with some of the species of Inocaulis. 

 It is possible to approach the same fossils from the study of 

 graptolites and arrive, as the present writer has actually done, at the 

 belief that they are graptolites of the group of Inocaulis which Mr 

 White would be inclined to take over into the algae. The points 

 which in this view are considered as of greatest importance are that ■ 

 while these bodies indeed are in general habitus extremely similar to 

 algae, they are connected by an uninterrupted series of stages with 

 the species of Inocaulis and Acanthograptus occurring in the 

 Niagaran of Hamilton, Ontario, and elsewhere, that lead again dis- 

 tinctly to Dictyonema and other undoubted graptolites. Some of 

 these species, as Inocaulis vegetabilis, 1 I. r a m u - 

 losus (ibid. p. 50), diffusus (ibid, p.' 53) and plumu- 

 1 o s u s Hall, 2 ' are indeed of strongly algal aspect, nevertheless they 

 occur not only associated with undoubted graptolites, but exhibit 

 the same strong carbonaceous residue as the graptolites, and the 

 same filamentous composition. The latter is, as we have pointed out 

 in I. plumosa, a true dendroid graptolite structure. Wiman 3 

 has even succeeded in etching a species of Inocaulis ( Inocaulis 

 musciformis ) out of limestone, and demonstrating its identity 

 of structure and of the thecal composition with that of Dictyonema. 

 It is true a like filamentous structure is found in the very similar 

 green alga Codium, but aside from the fact that it is quite doubtful 

 that the unicellular filaments composing that alga would be able to 

 furnish the strong threads or tubes seen in Inocaulis les- 

 quereuxi, it is in our view conclusive that the filaments of 

 I. lesquereuxi all terminate in pores on the surface of the 

 fossil, and therefore presumably represent actual tubes. We have 

 reproduced in plate 4, figures 1, 2 and 4, these apertural portions of 

 the thecal tubes, that as a rule are perpendicular to the surface of 

 the rhabdosome, and a comparison of this structure with that 

 described of I. plumosa by the writer will show their essential 

 identity. 



1 See Ray S. Bassler : "Dendroid Graptolites of the Niagaran Dolomites 

 of Hamilton, Ontario." U. S. Nat. Mus. Bui. 65, pi. 5, fig. 1. 1909. 



2 See Ruedemann, R. " Graptolites of New York," pt 2, N. Y. State Mus. 

 Mem. 11, pi. 7, figs. 1 and 2. 1908. 



3 Wiman, Carl. Ubef die Borkhokner Schicht im Mittelbaltischen Silurge- 

 biet. Bui. of the Geol. Inst, of Upsala, no. 10. v. 5, pt 2. 1900. 



