494 Palaeontologie. 



lateral lobes are borne on short lateral stalks. The larger 

 pinnules sometimes bear a second pair. The sporangia appear 

 to be smaller than in C. saglttata and they are not well pre- 

 served. The spores are also smaller and somewhat triangulär 

 with a thin exospore. 



Myriotheca is represented by a single species, apparently 

 identical with Lesquereux's Sphenopterls scaberrlma. The 

 absence of an annulus has led Zeil ler to include both Crosso- 

 theca and Myriotheca in the Marattiaceae, but Mr. Sellards 

 points out that the position of the sporangia is unusual in the 

 Marattiaceous ferns. 



Four other species of ferns have their spores preserved 

 in a very perfect condition. Pecopterls unita Brongn. and P. 

 villosa Brongn., were studied with special reference to possible 

 heterospory, but they were found to be unquestionably homo- 

 sporous, a fact of special interest in view of Renault's deter- 

 mination of supposed heterospory in a European Pecopterls, but 

 the author points out that the mere presence or absence of 

 the triradiate lines which so commonly characterize the spores 

 of the higher Ptertdophyta, cannot be accepted as a means of 

 distinction between macro- and microspores as adopted by 

 Renault. D. P. Penhallow. 



WHITE, David, A new name for Buthotrephis dlvaricata D. W. 

 (Proc. Biol. Soc. Wash. Vol. XV. April, 1902. p. 86.) 



The name Buthotrephis dlvaricata given to an alga from 

 the Upper Silurian at Kokomo, Indiana (Proc. U. S. Nat. Mus., 

 Vol. XXIV, 1901, p. 265, pl. XVI), has since been found to have been 

 preoccupied by Kids ton for a species from the Wen lock 

 Shales of Shropshire. The specific name B. spectosa is there- 

 fore substituted. D. P. Penhallow. 



White, David, Description of a Fossil Alga from the 

 Chemung ofNewYork, with rem arks onthe genus 

 fialtserltes Sternb. (Rept. N. Y. State Paleontologist for 1901. 

 p. 594—610. pl. 3 and 4.) 



Describing two remarkably well preserved specimens of an 

 alga from the Chemung at East Windsor, N. Y., Mr. 

 White introduces a new generic name — Thamnocladus — 

 as applicable to the intricate, copselike growth of the fronds, 

 while carefully avoiding all implication of relationship to any 

 particular family of living algae. The fronds are described as 

 „ramose, alternately dichotomus from the base upward, more 

 or less elongated ; lamina fleshy, linear convex or subcylindric, 

 tapering gradually and traversed by a cortical axis or Strand". 

 Only one species — T. Clarkel — is recognised, but this 

 appears in such condition as to leave no reasonable doubt as 

 to its plant nature. Among recent forms, the fossil seems to 

 suggest Hallserls delicatula, while it is also comparable with 



