204 PROCEEDINGS OF THE ACADEMY OF [1879. 



At this season the Cristatella groups are full of statoblasts or 

 winter eggs, in all stages of development. The mature stato- 

 blasts, including the annulus, but excluding the marginal anchor 

 spines, measure from 1.15 mm. to 1.225 mm. in breadth. Of fifteen 

 specimens, seven measured 1.2 mm. in breadth. The number of 

 anchor spines usually ranges from 60 to 70 ; but in a few speci- 

 mens as low as 53 and as high as 74 were counted. Both in size 

 and the number of spines they considerably exceed those of Cris- 

 tatella mucedo and C. ophidoidea. 



The individual polyps of Cristatella Idae when fully extended 

 are about 3 mm. in length, and their arms support about 80 

 tentacles. The stomach is chocolate brown; sometimes lighter 

 yellowish or greenish-brown. 



The same locality was further remarkable for its profusion of 

 other animals, especially for the abundance of flesh-colored Hydras, 

 and the groups of Vorticellas. Tufts of Anacharis were white 

 from the latter. 



Lieut. C. A. H. McAuley, U.S. A., was elected a correspondent. 



October 7. 

 The President, Dr. Ruschenberger, in the chair. 

 Thirty persons present. 



On Amoeba Blaltse Prof. Leidy remarked that while perusing 



the communication of Prof. Biitschli on "Flagellata and other 

 related Organisms" (Beitrage zur Kenntniss der Flagellaten und 

 einiger verwandten Organismen), in the Zeitschrift fur wissen- 

 schaftliche Zoologie, 1878, 205, his attention was especially at- 

 tracted by the description of a parasitic amoeboid living in the in- 

 testine of the cockroach, Blatta orientalis. It recalled to mind 

 that he had observed the same creature a number of years ago, 

 in association with the ciliated infusorian he had described as 

 Nyctotherus ovalis. At that time he had viewed it as a young 

 form of a Gregarina, and had intended giving it and other para- 

 sites of the cockroach more critical examination, but failed to do 

 so. The parasitic amoeboid, which Prof. Biitschli describes under 

 the name of Amoeba Blaltse is particularly interesting on account 

 of its habit and its somewhat peculiar character. Prof. L. had 

 recentty examined some cockroaches, and found abundance of the 

 amoeboid in association witli Nyctotherus ovalis, Lojihomonas blat- 

 tarum, Oxyurus gracilis, and 0. appendiculatus, and an algoid 

 plant. 



The amoeboid he thought was worthy of a generic distinction 

 from the true Amoeba holding a position between this and Prota- 

 moeba. Prom the former it differed in the absence of a contractile 

 vesicle and commonly also of vacuoles, and in the want of diner- 



