218 BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



Family CONSTELLARIID^ Ulrich. 



Until the publication of the Enghsh edition of Zittel's Textbook of 

 Paleontology, the members of this family were assigned to the 

 Trematoporidse, a position which increasing knowledge has shown 

 to be unwarranted. In a general way the wall structure of Constel- 

 laria and its allies is similar to that obtaining in the other families of 

 the Amalgamata, but other characters are so different that a new 

 family, Constellariidse, was instituted by Ulrich in the above-men- 

 tioned publication. The most obvious characteristic of the family 

 is the usually stellate shape of the maculae. More important features 

 are the small, hollow spines or granules which occur in place of true 

 acanthopores, and a somewhat granular wall structure occurring in 

 the more mature portion of the zoarium. 



The simplest type of Constellariidse is believed to be expressed in 

 Dianulites, which, although it lacks the stellate maculae, has the 

 characteristic granulose wall structure and the small granules or 

 hollow spines in place of acanthopores. Dianulites was at first 

 beheved to be restricted to the Baltic Ordovician deposits, but a 

 single large typical species of the genus is now recognized in America. 

 Typical species of Oonstellaria, Stellipora, and Nicholsonella occur in 

 both America and Russia. The remaining genus of the family, 

 Idiotrypa, is known only from early Silurian rocks and has not been 

 noted elsewhere than in North America. 



Genus CONSTELLARIA Dana. 



Constellaria Dana, Zoopliyta, 1846, p. 537. — Nicholson, Pal. Ohio, vol. 2, 1875, 

 p. 214; Pal. Tab. Corals, 1879, p. 292; Genus Monticulipora, 1881, p. 97.— 

 Ulrich, Joum. Cincinnati Soc. Nat. Hist., vol. 5, 1882, p. 156; vol. 6, 1883, 

 p. 265. — ^James and James, Joum. Cincinnati Soc. Nat. Hist., vol. 11, 1888, 

 p. 29.— Ulrich, Geol. Surv. Illinois, vol. 8, 1890, pp. 374, 423; Geol. and Nat' 

 Hist. Surv. Minnesota, vol. 3, pt. 1, 1893, p. 311; Zittel's Textbook of Paleon- 

 tology (Eng. ed.), 1896, p. 276. — ^J. F. James, Journ. Cincinnati Soc. Nat. 

 Hist., vol. 18, 1896, p. 117.— Nickles and Bassler, Bull. 173, U. S. Geol. 

 Surv., 1900, p. 34. — Cumings, Thirty-second Ann. Rep. Dep. Geol. Nat. 

 Res. Indiana, 1907, p. 742. 



Stellipora Milne-Edwards, Hist. Nat. des Corall, vol. 3, 1860, p. 281. 



Stellipora (part) Dtbowski, Die Cbaetetiden d. Ostbalt. Silur-Form., 1877, p. 42. 



The generic characters of this group of Bryozoa have been worked 

 out and described by Ulrich in his various memoirs. The genus is 

 one of the most easily recognized of Ordovician and early Silurian 

 types, mainly on account of the very characteristic star-shaped 

 maculae. This, although the most obvious feature, is no more impor- 

 tant than the erect ramose or frondescent growth and the minute 

 structure of the walls. Nickles and Bassler have briefly defined the 

 genus as follows: 



Zoarium growing into erect, flattened branches or fronds from a basal expansion 

 which is attached to foreign bodies; surface with depressed stellate maculae, the 



