ulrich-bassler] revision of paleozoic bryozoa 279 



Vine's VincUa re pens var. contorta (loc. cit.) is founded on a speci- 

 men of this species, but we could not satisfy ourselves concerning 

 this identity. 



Occurrence. — Common in the Silurian of Gotland, probably also 

 in the Wenlock shales of England. 



Cat. No. 43,133, U. S. N. M. 



HETERONEMA? CONTEXTUM new species 



(Plate LXV, 12) 



The specimen upon which this species is founded forms a con- 

 siderable patch over the celluliferous surface of a species of Lepto- 

 trypa, which had attached itself to the shell of an Orthoceras. The 

 Heteronetua ? is pyritized and in its present condition has a dark 

 color. It forms a delicate though very irregular and often spiny 

 network, the meshes of which are faithfully represented in plate lxv, 

 [2. Whether the network was originally produced chiefly by the 

 mere crossing of threads, or was wholly the result of this frequent 

 bifurcation and anastomosis, cannot now be determined. The rela- 

 tion of the meshes to each other, however, inclines us to regard the 

 latter explanation as more likely to prove true. Small, elevated 

 points, occurring principally on the intersections, may represent pores. 



The placing of this fossil under Heteronema can be defended only 

 as a temporary arrangement. Indeed, we shall not be surprised if it 

 proves to be not even a bryozoan. It may be a sponge. 



Occurrence. — Corryville bed, Lorraine formation, Morrow, Ohio. 



Cat. No. 43,132, U. S. N. M. 



HETERONEMA CARBONARIUM new species 

 (Plate LXV, 13) 



This species is distinguished from H. capillare on account of the 

 greater strength and comparative rigidity of its threads. These are 

 also more flattened, and hold a nearly uniform width, the extremes 

 scarcely exceeding the difference between 0.06 mm. and 0.07 mm. 

 A slight, transverse wrinkling of the surface may be observed, but 

 as we could not satisfy ourselves that the feature is characteristic of 

 the species, it was not shown in our illustration. 



Occurrence. — Lower Coal Measures, Seville, Illinois. 



Cat. No. 43,132, U. S. N. M. 



Genus Allonema new genus 

 1884. Rhopalonaria (part) Vine, Ann. Mag. Nat. Hist., sen 5, xiv, p. 

 85. fig- IV, 3. 



