24 PROCEEDINGS OP THE ACADEMY OF 



Preserving the animals for observation, on returning after an 

 absence of three hours, the animals were observed connected by 

 a broad isthmus including the granular sphere reduced to half 

 its original diameter. Two hours later the granular sphere had 

 melted in the isthmus, leaving behind Avhat appeared to be a large 

 oil globule and half a dozen smaller ones. The isthmus in the 

 former time measured -^^^ mm., at the later time -^-^ mm. 



Shortl}^ afterwards, the isthmus elongated and contracted to 

 gL mm. on the left, while the right half, retaining the oil globules, 

 remained as thick as before. At the same time the animals be- 

 came flattened at the opposite poles. The latter subsequently 

 became depressed so that the animals assumed a reniform outline. 



The isthmus now more rapidly narrowed and elongated, became 

 a mere thread, and finally separated about one hour from the last 

 two hours indicated. 



The oil globules were retained in the right-hand individual, 

 which, with the remaining projection of the isthmus, appeared 

 broadly codiform in outline. In the left-hand individual all remains 

 of the isthmus at once disappeared, and the animal appeared reni- 

 form in outline, but now contracting on the same side it assumed 

 the buscuit form. The constriction rapidly increased, and in 

 thirty minutes from the time of separation from the right-hand 

 individual it divided into two separate animals presenting the or- 

 dinary appearance of A. sol. Thus this second division took 

 place in an opposite direction from the first. 



The right-hand individual, retaining the oil globules apparently 

 unchanged, more slowly assumed the reniform outline, and then 

 became constricted all around. The constriction elongated to an 

 isthmus, in the centre of which were the oil globules. Three 

 hours after the separation of the right-hand animal, the isthmus 

 was narrowed to about half the diameter of the two new indi- 

 viduals which were about to be formed. At this moment other 

 engagements obliged me to leave the examination of the animals. 

 Six hours after, in the animalcule cage, I observed only half a 

 dozen individuals of the A. sol. 



March 31. 

 The President, Dr. Ruschenberger, in the chair. 

 Sixteen members present. 



The following papers w^ere presented for publication : 



" On Variations in Structure of Horns of Deer of the Genus 

 Cariacus." By E. D. Cope, A.M. 



" On the Ziphius of Nantucket." By E. D. Cope, A.M. 



On report of the committees, the following papers were ordered 

 to be pu)>lished : 



