Dr. Engelmann remarked that the mouth of the Ohio was some 

 300 feet above the level of the Gulf, so that, as far back as the 

 present configuration of the country existed, the gulf or delta, if 

 such an inappropriate name should be chosen, could never have 

 extended as high up as that point. 



Judge Holmes replied that the gradual elevation of the conti- 

 nent, with a change of level, might explain how the bottom of 

 the valley had been considerably raised, and that as the Gulf gra- 

 dually retired down the valley the alluvial deposits from the river 

 would follow the retiring ocean down to where the salt and fresh 

 waters now meet ; the river constantly raising its immediate banks 

 above the general level of the alluvial plain. 



Dr. Copes stated that, according to his recollection, the projec- 

 tion of the river deposits and delta into the Gulf was now going 

 on at the rate of one mile in fourteen or sixteen years. 



Mr. Rile)- exhibited a living specimen of Menobranchus late- 

 ralis, caught in Meramec river. Some years ago, he had caught 

 the same species in Lake Michigan. He also exhibited flowers 

 of the Physianthus albens, of which he had spoken at a former 

 meeting, and which held captive by their tongues a number of 

 different owlet moths {Noctitidtc) and some large Sphinx moths, 

 especially Deilephila lineata. This climbing plant belongs to 

 the Asclepiadacea: ; the brown, ovoid corpuscles, peculiar to the 

 stigma of this family, catch in their cleft the moth's tongue or any 

 thread-like body that gets into it, and, together with the pollen- 

 masses connected with them, are torn off from their attachment. 

 Firmly adhering to the tip of the tongue, they prevent its with- 

 drawal whenever, in seeking honey, it gets into the narrow groove 

 formed by the stiff' antheral projections. A moth is sometimes 

 thus held by a single corpuscle, and though, when once captured 

 such a moth may break loose, it would seem to be always at the 

 sacrifice of a part of its tongue, judging from the number of 

 tongue fragments found in the flowers. The holding power of 

 these flowers appears wonderful when we reflect on the size and 

 muscularity of the larger Sphinx moths. Nerium oleander was 

 known to catch Sphinx moths in Europe in a somewhat similar 

 way, and Oenothera grandijlora by a different method. 



Mr. Riley also offered a brief paper on the oviposition of the 

 Yucca moth. Referred to Publication Committee. 



