Maryland Geological Survey 269 



Occurrence. — Helderberg Formation, Keyser Member. Keyser, 

 West Virginia. 



Collection. — U. S. National Museum. 



Chilotrypa constricta (Hall) 

 Plate L, Figs. 13-15 



Trematopora ? constricta Hall, 1883, Rept. State Geol. N. Y. for the year 1882. 



pi. X, figs. 14-19. 

 Diamesopora constricta Hall and Simpson, 1887, Pal. N. Y., vol. vi, p. 19, pi. x, 



figs. 14-19; pi. xxiiio, fig. 7. 



Description. — This neat little species is readily distinguished from all 

 the associated ramose bryozoa, first by its hollow branches, with their 

 inner surface covered by an epitheca, and second by the strongly elevated 

 margin of the zooecial apertures. Measuring in a longitudinal direction 

 7 to 8 zooecia are found in 2 mm. 



The arrangement of the apertures is usually in the regular alternating 

 and imbricating manner shown in fig. 14, although occasionally they are 

 less regular as indicated in fig. 15. 



Occurrence. — Helderberg Formation, New Scotland Member. 

 North foot of Moore Knob, Washington County. 



Collection. — U. S. National Museum. 



Suborder TREPOSTOMATA 

 Family HETEROTRYPIDAE 



Genus CYPHOTRYPA Ulrich and Bassler 



Cyphotrypa corrugata (Weller) 



Plate XLII, Figs. 5-9 ; Plate XLIV, Fig. 4 ; Plate LII, Figs. 1, 2 



Monotrypa corrugata Weller, 1903, Geol. Surv. N. J., Pal., vol. iii, p. 223, pi. 

 xviii, figs. 1-5. 



Description. — Zoarium forming petasiform, hemispherical or rounded 

 masses from 15 to 50 mm. in diameter; basal side usually epithecated; 

 maculae' not elevated, consisting of large zooecia, the largest attaining 



* In the terminology heretofore in use, the term " macules " is generally 

 restricted to spots or clusters of cells composed principally of mesopores or 

 closed vesicles, but as these clusters are morphologically the same in all the 

 types of bryozoa having them, it will be conducive to uniformity in description 

 to apply the one term " macute " to all clusters, whether composed of meso- 

 pores, closed vesicles, or merely of larger zocecia." 



