NO. 5 ORDOVICIAN BRYOZOA — BOARDMAN I7 



p. 124), has never been validated. The species Ulrich might have 

 been referring to is Batostoma variabile Ulrich, 1890. 



"Amplcxopora cingulaia Ulrich" is mentioned on page 126 of the 

 October publication but was not described and figured until the 

 December number. Therefore, A. cingulaia is considered not to have 

 been available as the type species of Amplcxopora. 



One of the two valid species, "Amplcxopora discoidea, James" 

 (Ulrich, 1882, p. 123), should have been cited as A. discoidea 

 (Nicholson). James first listed the name in 1871 without indication, 

 definition, or description. Nicholson borrowed James's types and 

 described them as Chaetetes discoidcus James (Nicholson, 1874, 

 p. 511, pi. 30, figs. 4-4d) thereby making himself the author of the 

 species. The whereabouts of the primary types is unknown. 



"Amplcxopora septosa Ulrich" is the second valid species men- 

 tioned in the October number (p. 128). This citation is in error, 

 lacking the parentheses around the author's name, as the species 

 was originally placed in Atactopora (Ulrich, 1879, p. 125). How- 

 ever, Ulrich removed any doubt as to the species referred to by 

 stating that Atactopora septosa belonged to Amplcxopora (1882, 

 pt. 2, p. 255). Atactopora septosa Ulrich, 1879, is here designated 

 the type species of Amplcxopora. 



Emended definition. — Zoaria are ramose, frondescent, incrusting, 

 or massive, and monticules are generally well developed. In the 

 exozone, wall structure commonly appears integrate, but can be 

 amalgamate. Laminae from adjacent zooecia intersect a sharply de- 

 fined zooecial boundary at angles of less than 90 degrees to form 

 a V-shaped pattern pointing distally. Distinct zooecial Hnings are 

 present in several species. Laminae of the diaphragms are continu- 

 ous distally with the laminae of these zooecial linings, or in other 

 species, with the zooecial wall laminae. Diaphragms are extremely 

 variable in thickness, curvature, parallelism, and spacing, with com- 

 pound and cystoidal diaphragms and cystiphragms common in many 

 species. 



Mesopores are lacking to few : early chambers are beaded and 

 later diaphragms are regularly and closely spaced. Acanthopores 

 are generally abundant and are of two types: those that are concen- 

 trated in zooecial corners and extend throughout the width of the 

 exozone, occurring in all species ; and additional acanthopores that 

 are concentrated between zooecial corners and extend through a part 

 of the exozone width, occurring in some species. These additional 



