82 PEOCEEDINGS OP THE NATIONAL MUSEUM vol.67 



are cylindrical, polygonal, crossed by numerous diaphragms; the 

 walls are thick, vesicular, peiforated, and united with the visors. 



Genotype. — Neurofora convligera Heimig, 1893, Cretaceous. The 

 genus was at first referred to the bryozoa; then it was classed among 

 the hydroids, but in 1893 Hennig's study of the genus definitely 

 established its structure. The Lower Cretaceous species are simpler 

 and less well characterized than those of the Upper Cretaceous. 



The veinules are formed by solidified tubes. We are ignorant of 

 their physiological function. 



NEUROPORA RAMOSA, new species 



Plate 25, figs. 9-12 



Description. — The zoarium is free, ramose, borne on a very small 

 base, with the branches often pyriform. The orifices are rather large, 

 polygonal, arranged in quincunx, ornamented with tubercles at the 

 angles. The veinules are irregular and converge toward the extrem- 

 ity of the lobes. 



Measurements. — Diameter of the orifice, 0.12 mm. 



Affinities. — The form of some zoaria approaches that of typical 

 Neuropora, but such specimens are rare. The lobes become elongated 

 generally into veritable branches, although pyriform also. In longi- 

 tudinal sections the tubular walls are thick, formed by a compact tis- 

 sue which corresponds to the exterior tubercles. The tubes, solidified 

 and meeting at the point of convergence of the veinules, are some- 

 what wider than the others. The sections of this species are very 

 opaque and difficult to interpret. 



Occurrence. — Lower Cretaceous (Valangian) : Sainte-Croix (Vaud), 

 Switzerland. 



Cotype.—C&t. No. 69875, U.S.N.M. 



NEUROPORA ARBUSCULA, new species 



Plate 25, figs. 1-3 



Description. — The zoarium is free, cylindrical, arhorescent, with 

 short branches. The orifices are polygonal, arranged in quincunx, 

 ornamented with a lateral somewhat salient tuberosity. The vein- 

 ules are irregular and longitudinal. 



Measurements. — Diameter of orifice, 0.10 mm.; width of zoarium, 

 6 mm. 



Affinities. — In the exterior aspect this species is very close to 

 Neuropora pyriformis, but it differs in its cylindrical zoarium, its 

 much broader base, and its somewhat smaller zooecial diameter. 



Occurrence. — Lower Cretaceous (Valangian): Sainte-Croix (Vaud), 

 Switzerland. 



Cotype.—C^i. No. 69876, U.S.N.M. 



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