ulrich-bassler] revision of paleozoic bryozoa 285 



We are not satisfied that this neat but very minute species is prop- 

 erly classified, but, as no fitter disposition suggested itself, we trust 

 the arrangement may suffice until increasing knowledge enables us to 

 fix its systematic position definitely. 



Occurrence. — Upper Coal Measures, Springfield, Illinois. 



Cat. No. 43,124, U. S. N. M. 



Family ASCODICTYONID^ Ulrich (restricted) 



From the viewpoint of the systematist, perhaps the most notable 

 result of this revision of the Paleozoic Ctenostomata is the restric- 

 tion of this family to the typical genus. Something of this sort, how- 

 ever, was to be expected, since the classification of these obscure 

 bryozoan remains hitherto in force was always regarded as a most 

 provisional arrangement. 



Genus AscoDiCTYON Nicholson and Etheridge, Jr. 



1877. Ascodictyon (part) Nicholson and Etheridge, Jr., Ann. & Mag. 

 Nat. Hist., sen 4, xix, p. 463. 

 h. Ascodictyon Vine, Quart. Jour. Geol. Soc. London, xxxvii, p. 618. 

 ?2. Ascodictyon Vine, Ibid., xxxviii, p. 52. 

 1884. Ascodictyon Vine, Rep. 53d Meeting Brit. Assoc. Adv. Sci., p. 185. 

 1884. Ascodictyon Vine, Ann. & Mag. Nat. Hist., ser. 5, xiv, p. 78. 

 1887. Ascodictyon Vine, Proc. Yorkshire Geol. & Polyt. Soc, ix, p. 183. 

 9. Ascodictyon Miller, North Amer. Geol. and Pal., p. 293. 

 0. Ascodictyon Ulrich, Geol. Surv. Illinois, viii, p. ^,67. 

 2. Ascodictyon Vine, Proc. Yorkshire Geol. & Polyt. Soc, xii, p. 86. 

 1897. Ascodictyon Simpson, Fourteenth Ann. Rep. State Geol. New 



York for 1894, p. 603. 

 1900. Ascodictyon Nickles and Bassler, Bull. U. S. Geol. Surv., No. 

 173, p. 19- 

 Zoaria parasitic, consisting of ovate or pyriform vesicles, arranged 

 in radial clusters or isolated, and connected with each other by very 

 delicate, hollow threads. Walls of vesicles perforated by closely 

 arranged, minute pores. Zooecia unknown. 



Genotype. — A. stcllatuin Nicholson and Etheridge, Jr. 

 Although A. fusiforme follows the generic description in the orig- 

 inal publication, and for that reason is usually cited by cataloguers as 

 the genotype, it is very evident that the authors of the genus regarded 

 A. stellatum as the type. This is shown by the italicized words in 

 the following quotation from their generic diagnosis : " In some cases 

 they [the vesicles] open into one another by short contracted necks 

 or stolons, thus forming a loosely reticulate network ; whilst more 

 typically they are arranged in regular, usually stellate clusters, which 

 in turn are united with one another by delicate thread-like hollow 



