NATURAL SCIENCES OF PHILADELPHIA. 157 



tion would prevent the formation of such a membrane, especially 

 after the cells had lost much of their vitality by being converted 

 into depositions of starchy or other mattei*. Hence we found but 

 the finest membrane covering the cotyledon faces. 



He could not understand how the facts exhibited accorded with 

 the earl}^ division into cot3dedons by actual growth, as taught in 

 our leading botanical works. For himself, he felt that botanists 

 would yet come to regard all seeds as non-cotyledonous in their 

 early stages ; and that the divisions into cotyledonous lobes ivas a 

 mechanical result determined in a great measure b^"^ the position 

 of the germinal vesicle without the cotyledonous mass. 



Mr. Meehan also referred to remarks he made on a former occa- 

 sion in regard to the sensitive clasping of the stigraatic divisions 

 of the pistil in Torenia asiatica. He had since found the same 

 phenomenon in 3Iimulus, Lindernia, and Diplacus; allies of the 

 Torenia. He did not know that this irritable closing power 

 had been placed on record au3Mvhere; but as there were hybrids of 

 Mimulus in cultivation, the fact could not but have been noticed 

 by cultivators at some time. In Mimulus the motion was more 

 rapid than in others he had tried. 



June 13. 

 The President, Dr. Ruschenberger, in the chair. 

 Twenty-seven members present. 



The following papers were offered for publication: — 



"Notice of a new Brachiopod from the Lead-bearing rocks at 

 Mine La Motte, Mo." By F. B. Meek. 



"Descriptions of three new species of Exotic Unionid^e." By 

 Isaac Lea. 



" Descriptions of twenty new species of Unionidse of the United 

 States." By Isaac Lea. 



Prof Cope made some extended observations on the supposed 

 orders of Plectognathi and Lophohranchii of Cuvier, of which the 

 following is an abstract : He stated that, after an examination 

 of their structure, he could not regard them as divisions of equal 

 value with the Physostomi and Fhysoclysti, etc. He stated that 

 the Plectognathi are Physoclysti in all respects, viz., the relations 

 of the supra-occipital to the other cranial bones, the structure of 

 the scapular arch, hj^oid and branchial arches, in the relations of 

 the dorsal and ventral fins, structure of basis of caudal fin, of 

 swim-bladder, etc. The family Teuthyes, among other Physoclysti, 

 formed the nearest approach to them, and that the coalescence of 

 1871.] 



