DESCRIPTION OF SPECIES 157 



creeping, branching, partially or entirely embedded in the host; com- 

 posed, as far as is known, of relatively large ovoid, pear-shaped, or 

 fusiform bodies or internodes, without regular arrangement, connected 

 by minute, branching tubular filaments or stolens. Internodes marked 

 by a few rather large pores scattered irregularly over the surface. 

 Zooecia unknown, but probably deciduous and developed by budding 

 from the surface pores as in the genus Hhopalonaria. 1 



In its generic relationships this genus apparently lies midway 

 between Rhopalonaria and Allonema of the Family Vinellidae, and is 

 characterized by its ability to excavate and disintegrate the host, by 

 the laige size and irregular arrangement of the excavations which have 

 been filled with foreign material so that they appear on the inside of 

 the host as ovate bodies. It differs from the genus Rhopalonaria in 

 the larger size, ovate shape, and irregular arrangement of the inter- 

 nodes, which in the latter genus have a pinnate arrangement. It can 

 be distinguished from both Allonema and Ascodictyon by its ability to 

 excavate the host. It resembles Allonema in the ovate form and irreg- 

 ular arrangement of the internodes but lacks the finely punctate sur- 

 face of that genus; it may also be distinguished by the. minute filament 

 connecting the internodes. Ascodictyon may be distinguished likewise 

 not only in the minute surface punctae on the vesicles, but also in the 

 stellate oV more regular arrangement of the vesicles. 



Genotype. Bascomella gigantea n. sp. Found in the McArthur 

 limestone, of the upper Pottsville formation of Ohio. This genus is 

 named in honor of Dr. Florence Bascom, Professor of Geology at Bryn 

 Mawr College. 



Bascomella gigantea n. sp. 

 PL VI figs. 18-20 



Description. Zoarium creeping, partially, or as is generally the 

 case, entirely embedded in the host, sometimes covering the entire 

 inner surface of the shell on which it is parasitic. Ovoid bodies typi- 

 cally pear-shaped but often fusiform or irregular in outline; arrange- 

 ment irregular; narrow pointed end depressed, broad blunt end con- 

 stricted near base ; formed by the filling of the excavation with sediment ; 

 an ovoid body of average size measuring: length 2 mm., width .8 mm., 

 height 1 mm.; surface apparently pierced by rather large, distant, 

 irregularly arranged pores. Minute, tubular filaments or stolens con- 

 nected with any portion of the ovoid bodies, but generally with the 

 base; one or several growing from each excavation; branching frequently 

 and forming an irregular network. 



Remarks. This species of boring bryozoan is extremely abundant 

 in the McArthur limestone at Monroe Furnace, Jackson County, but 



'Ulrich, E. 0., and Bassler, R. S., Smithsonian Miscell. Coll., Vol. 45, p. 267, 1904. 



