28 



the toothed portion of the bone ranging from 2.9 to 3.4 and 

 averaging more than 3 in twenty measured specimens whose 

 length ranged from 2f to 6 inches. The inner angle (i.a.) is 

 quite obtuse, 120' to 140". and the outer margin {o.iii.) is straight 

 or slightly inbent from the tip of the posterior spur [j). sp.) to 

 the anterior extremity {ant.) of the bone. The lower phar- 

 yngeals of Eiijxthiotis rjihhosus are deep and broad, with infe- 

 rior and lateral prominences, never being flattened or hollowed 

 out underneath as in L. pnUidus. Measurements made on 

 twenty specimens, from 2A to 6 inches in length, show a varia- 

 tion of only 1.9 to 2.5 (average 2.17) in the ratio of width to 

 length of the toothed portion, and a range of 95° to 111° in the 

 inner angle. The outer margin of the pharyngeal in this spe- 

 cies presents a double curve, with a moderate sinus situated pos- 

 teriorly, immediately in front of the spur, and a more or less de- 

 cided anterior arcuation, margining a lateral ledge-like promi- 

 nence. The spur is directed more or less definitely outward, 

 rather than backward as in L.paUidiis. The differences between 

 the teeth of these two species were found to be as hitherto 

 described, those of E. (jihhosus being short and heavy and either 

 very blunt or entirely paved, while those of L. palUdus ai'e long 

 and comparatively slender, with more or less acuminate tips. 

 An examination of the pharyngeal bones and their teeth 

 from specimens of E. hero.-i and E. Iio/hrooki'^ disclosed complete 

 conformity in those species to the type of bone and tooth found 

 in E. (jibhosus. The pharyngeals of £. r^»/'//'>r».s McKay proved, 

 however, to be of the pattern found in L paUldus. The phar- 

 yngeals of Apomofis cyaneUus, isc/njrus, and si/mmefricus, and 

 of L. )iii)iiaf)is. aiiritia^. mrf/alotls, occidodftli^i.^ humilis, and hap- 

 lo(/nfitli>ii> were also found to differ in no essential respect from 

 these bones as described for L. pxdlidus. The lower pharyngeal 

 teeth of A. cyaneUus, ischynis, and symmetricus, and of L. inin- 

 iafiis and E. euryonts appear as a rule to be somewhat less 



♦Through the courtesy of Dr. S. E. Meek, of the Field Columbian Museum, we 

 have been permitted to examine specimens of this and other species not found in the 

 waters of Illinois. 



'\L. occidentatis. Meek, Field Col. Mus., Zool. Ser., Vol. II., No. 6, p. ii8. 



