iu i.i I l in : \m mi \i 01 < OMPARATn E ZOO'LOGl . 



( KAMlDAl. 

 (KAMA I. U.I. I \ Hall. 



Crania laelia Hull, Descrip. Crinoidea etc., 1866, p. 131. 24th Rept. X. Y. 

 State cab. nut. hist., IS72, p. 220, pi. 7, fig. hi. Miller, Cine, quart, 

 journ. Bci., 1875, 2, p. 12. Hall and Whitfield, Pal. Ohio, is?:., 2, p. 7."), 



pl. 1, fig. hi. Hall and Clark.', Pal. N. Y ., L892, 8, pt . 1, pi. 11, fig, 1. 

 Grabau and Shinier, N. A. Index fossils, r.i<)7, 1, p. 297, fig. 242. Cum- 

 ings, 32d Ann. rept. Dept. geol. nat. res. Indiana, 1908, p. 897, p 

 fig. 2. 



Shell small, inequivalve, oval in outline, with width greater than 



length. Dorsal valve highly convex; beak elevated, pointed, situ- 

 ated nearly in the middle of the shell. 



Surface marked by concentric lines of growth as well as radial 

 striatums. The latter vary considerably in number and strength. 



This shell is quite common in the Maquoketa at Clermont, Iowa, 

 and is usually found attached to an orthid or Rafinesquina. In no 

 case was the Crania marked like the surface of the host. 



I.i>c<iliti/: — Maysville and Richmond; Cincinnati, Ohio, and many 

 localities in Ohio, Indiana, Kentucky, Tennessee, etc., Lower Maquo- 

 keta at Clermont, Iowa. 



Ortrtdae. 



The most recent fauna! lists have not adequately suggested the 

 variety of Orthidae to he found in the Maquoketa. Until quite 

 recently Plectorthis (Auslinetta) whitfieldi (X. II. >Yinchell) was the 

 only member of this common Palaeozoic family definitely identified 

 from the various outcrops in Iowa, Illinois, Wisconsin, and Minnesota. 



Plectorthis (Austinella) kankakensis (McChesney). 



Orthis kankakensis McChesney, New Pal. fossils, 1861, p. 77. Trans. Chicago 



acad. sci., 1868, 1, p. 29, pl. 9, fig. 3. 

 Plectorthis kankakensis Hall and Clarke, Pal. X. Y., 1892, 8, pt. 1, p. 221, pl. 5. 



fig. -24, 25. 

 Austinella kankakensis Foerste, Bull. sci. lab. Denison univ., 1909, 14, p. 224. 



The difference between P. kankakensis and P. whitfieldi is mentioned 

 in the discussion of the latter species. Both occur plentifull}' at 





