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 Ptilometridae 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 articular 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 coordinate 

 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 P b which is similar to P 2 but smaller, instead of 

 larger and more or less differentiated as in the Thalassometrinae. 



In 1924 Prof. Torsten Gisle"n accepted the family Thalassometridae with the 

 subfamilies Ptilometrinae 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 Gisl6n referred several times to the family Ptilometridae, 

 but did not formally define it. 



Genus PTILOMETRA A. H. Clark 



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



Comatula (part) J. MULLER, Monatsb. preuss. Akad. Wiss., 1846, p. 179. 



Kallispongia (part) WRIGHT, Proc. Roy. Irish Acad., ser. 2, vol. 2, 1877, p. 754. RIDLEY, Zool. 

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



Comalula (Antedon) (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 Comatula} macronema J. Miiller, 1841 [1846]); Bull. Mus. Comp. Zool., vol. 51, 

 No. 8, 1908, p. 245 (diagnosis; genotype Comalula 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. K0bcnhavn, 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 Sudwest- Australians, vol. 3, Lief. 13, 1911, p. 439 

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



