On the Structure and Affinities q/" Euphoberia. 437 



cells) as that of the remarkable contractile vesicle observed in 

 the pulmonate Gasteropoda, and which I have studied in 

 Limax. It is probable that the two parts are homogenous." 



So far as any comparison between the Cephalopod yelk-sac 

 and the Gasteropod foot is legitimate, it appears to me that I 

 had made it in the above passage some years since. 



As to the homologies generally of Gasteropod and Cepha- 

 lopod, I am inclined to agree with Mr. Brooks when he says 

 " we cannot expect any valuable results to follow from the 

 attempt to compare any part of the body of a Cephalopod 

 with structures which, like the epipodial folds, are not common 

 to the Gasteropoda, but somewhat exceptional." I consider 

 that a close relationship exists between the siphonal folds of 

 the Cephalopod and the " pteropods " of Pteropoda, and, again, 

 between the arms of the former and the arms (bearing suckers 

 in Pneumodermon) of the latter ; but there appears to be no 

 ground for going further when we compare these parts with 

 those of a Gasteropod than is involved in assigning them all 

 to " the foot," which certainly cannot be given up to the sole 

 equivalence of the yelk-sac, and is not to be limited, as Mr. 

 Brooks would have it, to an unpaired median growth. I do 

 not see the cogency of the arguments put forward by Jhering 

 for regarding the arms of Pteropods and Cephalopods as 

 distinct from foot ; and assuredly it is necessary absolutely to 

 reject Grenacher's notion of their identity with the velum, a 

 notion with which every morphologist has at one time or other 

 amused himself; and, lastly, there appears to be no ground 

 capable of statement for regarding, as Brooks would do, the 

 siphon (funnel) as a growth peculiar to the Cephalopod. Its 

 condition in Nautilus alone is sufficient to show that it is a 

 part of the molluscan foot. 



XLV. — The Structure and Affinities of Euphoberia, Meek 

 and Worthen, a Genus of Carho7iiferous Myrioijoda. By 

 Samuel H. Scudder*. 



The genus Euphoheria was established in 1868, for some 

 remarkable spiny Myriopoda found in the ironstone nodules 

 of Mazon Creek, in Illinois, and which were lirst fully de- 

 scribed and figured in the third volume of the Geological 

 Report of the Illinois Survey. The only characteristics then 

 noted, in which they differ from modern types, were the 

 tapering form of the body and the presence of branching 

 * From the ' American Jom-nal of Science,' March 1881, pp. 182-186. 



