334 PROCEEDINGS OF THE ACADEMY OF [1885. 



genus, the lower portions of the arms are connected laterally for 

 some distance by one or two rows of interbrachial pieces. 

 Angelin described under Polypeltes a single species : — 



1878. ? Polypeltes granulatus Angclin. Iconogr. Crin. Suec, p. 27, PI. 24, figs. 



2, 3. — Upper Silurian. Gothland, Sweden. 



MEGISTOCRINUS Owen and Shum., Rev. ii, p. 135. 



We compared Megistocr. Ontario Hall, and M. depressas Hall, 

 with good specimens in our own cabinet and in the Canada Sur- 

 vey Museum, and find the former to be a young example of if. 

 abnormis Lyon, the latter of M. rugosus Lyon and Cass. 



Additional species : — 



1879. M. pileatus S. A. Miller. Journ. Cinein. Soc. Nat. Hist. (December), PI. 10, 



figs. 1 a 1). — Corniferous limest. Columbus, 0. — This must be closely com- 

 pared with M. rugosus Lyon and Cass., with which it may be identical. 

 1885. M. concavus WaidiMiiuth. Proceed. Davenport Acad. Sci., vol. iv, p. 96, PI. 



1, figs. 5-7. — Alpena, Mich. 

 *1836. M. globosus (Phill.) Actinocr. globosus, Geol. Yorkshire, p. 206, PI. 4, figs. 

 26-29, also BffoCoy, 1844, Synops. Carb. Foss. Ireland, p. 182; W. and Spr. 

 Rhodocr. globosus, Rev. ii, p. 212. — Mount. limest. England. 

 1885. M. nodosus, var. multidecoratus Barris. Proceed. Davenport Acad. Nat. Sci., 

 vol. iv, p. 100. — Hamilton gr. Alpena, Mich. 



C. ACTINOCRINITES. 



ACTINOCRINUS Miller, Rev. ii, p. 138. 



Phillipsocrinus caryocrinoides McCoy, Synops. Carb. Foss. 

 Ireland, p. 183, PI. 26, fig. 5, is evidently an abnormal specimen 

 of Actinocrinus pusillus or some other closely allied species. 



Actinocr. dalyanus S. A. Miller, 1881, is a synonym of Actinocr. 

 proboscidialis Hall, and it is from the Lower Burlington lime- 

 stone, not from the Keokuk limestone, as supposed by Miller. 



A. tholus Hall. It is possible that the form which Hall de- 

 scribed under this name, and which we took to be a synonym of 

 .1. qlans, is more than a mere variety. We found lately in one 

 and the same locality numerous specimens agreeing well with 

 Hall's description, every one having convex or even slightly nodose 

 plates ; while those of A. glans are generally smooth or merely 

 convex, and the form of the body is somewhat more elongate. 



Additional species : — 



I8ft0. A. spinotentaculus Hall, Suppl. (ieol. Rep. Iowa, I, p. 86. — Lower Burlington 

 limest. — Burlington, Iowa. 



