254 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 



STttRTZASTER (?) MITCHELLI Etheridge, jr. 



Sturtzaster (?) mitchelH Etheridge, jr., Rec. Australian Miis., vol. 3, 1899, p. 128. 



Formation and locality. — A single specimen from the Upper Trilo- 

 bite bed of tbe Siluric (Wenlock series) at Bowning, New South 



Wales. 



Genus BDELLACOMA Salter. 



Palseocoma (Bdellacoma) Salter, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 



324. — Wright, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palse- 



ontogr. Soc. for 1861), 1862, p. 31.— Zittel, Handb. Pal., vol. 1, 1879, p. 



453. — STiJRTZ, Palaeontographica, vol. 32, 1886, p. 96. 

 Bdellacoma Sturtz, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 46, 



63. 



GenoJwlotijpe and only species. — P. (B.) vermiformis Salter. Lower 

 Ludlow, Leintwardine, England. 



Remarks. — Until this form is restudied and brought up to date the 

 supposed subgenus of Palseocoma has no value. 



Genus RHOPALOCOMA Salter. 



Palseocoma (Rhopalocoma) Salter, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, 

 p. 329.— Wright, Mon. Britisli Foss. Ecliinod., Oolitic, vol. 2, pt. 1 (Palse- 

 ontogr. Soc. for 1861 ), 1862, p. 31.— Zittel, Handb. Pal., vol. 1, 1879, p. 453.— 

 Stxjrtz, Palseontograpliica, vol. 32, 1886, p. 96. 



Rhopalocoma STtJRTZ, Verb, natiirh. Ver. preuss. Rheinl., etc., vol. 50, 1893, 

 pp. 46, 63. 



Genolwlotype and only species. — P. (R.) pyrotecJinica Salter. Lower 

 Ludlow, Leintwardine, England. 



Remarlcs. — This form also requires modernization, and until then 

 the supposed subgenus has no value. 



Genus HALLASTER Sturtz. 



Protaster Hall (not Forbes), Nat. Hist. N. Y., Pal., vol. 3, 1861, p. 134; 



Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 293; rev. ed., 1868= 



1870, p. 336. 

 Hallasier Stijrtz, N. Jahrb. fvir ]\Iin., etc., 1886, vol. 2, p. 150. 



Original description (Sturtz). — "Ambulacral plates alternating 

 [they are opposite]; the podial pores he between these and the side 

 plates. The dorsal skeleton consists of two columns of doreal plates 

 and two of lateral plates, of which the former adjom medially along 

 the rays. For P. forhesi Hall of the Silurian of North America I 

 propose the generic name Hallasier, because on the one hand Forbes 

 did not sufhciently characterize his Protaster, and on the other the 

 above species in the sense of Salter's Protaster is not congeneric 

 with it." 



GenoJiolotype and only species. — Protaster forhesi Hall. 



Remarlcs. — This genus appears to be most closely related to Lap- 

 worthura. with the most obvious difference in the shape of the am- 



