394 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



metridae, are very short, transversely linear (see Part 2, pp. 42-45, figs. 67, 68, p. 43, 

 figs. 973, 974, pi. 2); and the centrodorsal is large, columnar, with the cirri arranged 

 in 15 or 20 closely crowded and usually more or less irregular columns. 



Geographical range. — Southern Australia northward to Dirk Hartog Island on 

 the west coast and to the Clarence River on the east coast. 



Bathymetrical range. — From the shore line down to 113 meters. 



Remarks. — The species of the family PtUometridao agree in general with the 

 species of the family Asterometridae, but they differ radically in the very small size 

 of the muscular fossae of the artic^Ilar faces of the radials which are reduced to narrow 

 transverse bands along the distal borders of the interarticular ligament fossae, as 

 in the species of the family Calometridae, and less significantly in the structure of the 

 centrodorsal which, though higher, suggests the centrodorsal of the Tropiometridae. 



The family Ptilometridae includes only the genus Ptilometra. 



History.— The subfamily Ptilometrinae was first recognized in 1914 as coordiiiate 

 with the subfamily Thalassometrinae, the two subfamilies together making up the 

 family Thalassometridae. The subfamily Ptilometrinae, which included the genera 

 Ptilometra, Asterometra, and Pterometra, was distinguished from the subfamily Thalasso- 

 metrinae, solely on the character of Pi, which is similar to P2 but smaller, instead of 

 larger and more or less differentiated as in the Thalassometrmae. 



In 1924 Prof. Torsten Gisl4n accepted the family Thalassometridae with the 

 subfamilies PtUometrinae and Thalassometrinae, but he removed the genera Astero- 

 metra and Pterometra from the subfamily Ptilometrinae creating for them the new 

 family Asterometridae which he placed in the subtribe Notocrinida under the Thalasso- 

 metrida, the family Thalassometridae with the subfamilies Ptilometrinae and Tha- 

 lassometrinae remaining in the subtribe Thalassometrida. 



In 1934 Professor Gisl^n referred several times to the family PtUometridae, 

 but did not formally define it. 



Genus PTILOMETRA A. H. Clark 



Enerinus (part) Wilton, Tasmanian Journ. Nat. Sci., vol. 2, No. 7, 1843, p. 118. 



Comahda (part) J. MtJLLER, Monatsb. preuss. Akad. Wlss., 1846, p. 179. 



Kallispongia (part) Wright, Proc. Roy. Irish Acad., ser. 2, vol. 2, 1877, p. 754. — Ridley, ZooI. 

 Rec. for 1877, 1878, Spongida, p. 6 Spong. (erinoidlike ; doubtful if a sponge). 



Comatula (Antcdon) (part) P. H. Carpenter, Nature, vol. 15, 1877, p. 197. 



Antedon (part) P. H. Carpenter, Nature, vol. 15, 1877, p. 197, and following authors. 



Ptilometra A. H. Clark, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 358 (diagnosis; genotype 

 Alecto [that is Comatiila] macronema J. Muller, 1841 [1846]); Bull. Mus. Comp. Zool., vol. 51, 

 No. 8, 1908, p. 245 (diagnosis; genotype Comatula macronema); Proc. Biol. Soc. Washington, 

 vol. 21, 1908, p. 135 (referred to the Tropiometridae); Proc. U. S. Nat. Mus., vol. 34, 1908, 

 p. 211 (same); Amer. Nat., vol. 42, No. 500, 1908, p. 541 (only known from Indo-Pacific- 

 Japanese area); Geogr. Journ., vol. 32, No. 6, 1908, p. 602 (same); Smithsonian Misc. Coll., 

 vol. 52, pt. 2, 1908, p. 199 (discovered in the East Indies [refers to Pterometra]); Proc. U. S. 

 Nat. Mus., vol. 36, 1909, p. 365 (side- and covering-plates more or less imperfectly developed; 

 not found in the young) ; Zool. Anz., vol. 34, No. 11/12, 1909. p. 363 (tropical genus occurring in 

 southern Australia); Vid. Medd. Naturh. Foren. K0benhavn, 1909, p. 182 (amplification of the 

 generic characters; radial articular facets); Amer. Journ. Sci., ser. 4, vol. 32, 1911, p. 130 (signif- 

 icance of distinctive characters); Die Fauna Siidwest-Australiens, vol. 3, Lief. 13, 1911, p. 439 

 (confined to southern Australia; closely related to Pterometra and Asterometra which represent it 



