BRYOZOA. 48J 



little if any raised above it. Measuring from center to center they 

 are about 2.5 mm. apart. The maculae are surrounded by com- 

 paratively large apertures, facing outward; having the hood or 

 lunarium very prominent. Apertures oblique, sub-triangular or 

 pyriform, bidenticulate, hooded, about 0.15 mm. in diameter, 

 rather closely approximated, an average of twelve or thirteen 

 in three mm. Zooecia at first oblique, then direct. The primi- 

 tive cells, as shown by deep tangential sections, are of elongate 

 semi-cordate form, and arranged between longitudinal lines. 

 Here they sometimes show a feature that reminds me of a su- 

 perior hemiseptum. Diaphragms apparently wanting. Vesicles 

 varying in shape, angular, approaching in size to the zocecia. 

 In the upper part of the zoarium the vesicles are filled up or 

 replaced by solid calcareous matter, exhibiting in good sections 

 a large number of minute dark spots. 



The distinctive features of this neat and well marked species 

 are the small and closely approximated zocecia, the strong and 

 regular wrinkles of the epitheca, and the general resemblance of 

 the zocecial structure to that of the CYSTODICTYONID.E. Should 

 it prove that the form is bifoliate then it would have to be re- 

 garded as an unqualified species of Dichotrypa. In any event I 

 am strongly inclined to place it there. 



Position and locality: Hamilton group, Thunder Bay, Mich. 



FISTULIPOKA STELLIFERA Romiuger. 



PI. XLVII. fig. 2. 2a. 

 Fistulijpora steilifera Rominger. 1866. Proc. Acad. Nat. Sci. Phila. p. 120. 



Zoarium sometimes unilaminar, more commonly rising into 

 bifoliate expansions, from one to three mm. thick. Surface 

 nearly even, but sometimes the m acute are slightly elevated. 

 Maculae of stellate appearance, about four mm. from center to 

 center, the central portion and rays concave, smooth or finely 

 granular, appearing solid at the surface. Apertures oval or 

 circular, with prominent peristome, one side (lunarium) often 

 more elevated than the other. In perfect examples, the rim 

 bears from six to eight small blunt spines. The arrange- 

 ment of the zocecia apertures is quite regular, radial series being 

 the most marked around the maculae, where they are also 

 slightly larger and separated by wider interspaces than in the 

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