160 



BULLETIN" 11, UNITED STATES NATIONAL MUSEUM. 



recognize it since his specimens were imbedded in the rock, his illus- 

 trations and those of Lonsdale are undoubtedly based upon the 

 same species. The new names Pennireiepora and Penniretepora 

 lonsdalei of D'Orbigny are therefore superfluous. 



Glauconome, as here recognized, seems to be an undoubted member 

 of the Arthrostylidse, differing from all other genera of the family 

 in its continuous branching zoarium with the reverse side noncel- 

 luliferous. None of the many specimens of G. disticha and G. strigosa 

 before me shows any evidence of a basal articulation, so that it is 

 probable that the zoarium was attached at the lower end instead of 



Fig. 80.— Glauconome plumula. a to d, fragments of fotje zoaeia. e, noncelltjliferoijs sibe, 

 XIO; /, cellulifeeous face, xlO; ^and Ji, two transverse sections, XIO. Borkholm drift, Ojie 

 Myb, island of Gothland. (After Wiman.) 



jointed. With regard to the distribution of the apertures, Glauco- 

 nome bears the same relation to NeTnatopora that Arihrostylus has to 

 Helopora. 



Genotype. — Glauconome disticlia Goldfuss. Silurian of England 

 and Gothland. 



GLAUCONOME PLUMULA Wiman. 



Text fig. 80. 



Glauconome plumula Wiman, Bull. Geol. Inst. Univ. Upsala, vol. 5, pt. 2, No. 

 10, 1902, p. 181, pi. 6, figs. 17-24. 



This is undoubtedly a typical species of Glauconome closely related 

 to the genotype. My material for study consists of a poorly pre- 

 served specimen from the Lyckholm limestone, but Wiman's figures 

 clearly indicate the characters and relationship of his species. It 

 need only be compared with G. disticJia from which it differs, so far 

 as I can judge, only in branching a trifle more regularly and more 

 frequently, and in having sHghtly smaller zooecia less regularly 

 arranged. In G. disticlia the zooecial apertures are arranged in four 

 regular rows, two on each side of a conspicuous carina. Study of 



i 



