93 



shape of its body, the absence of a projecting point from the poste- 

 rior segment, and the existence of an elevated umbo on the back. 



He also exhibited specimens of Pyrosoma gigantea, referred to 

 him at a previous meeting, recently presented by Dr Yale. 



Dr. Binney gave the results of his observations made 

 during two successive summers at Nahant, on the habits of 

 the Orthogariscas mola, or short sunfish. 



He had found it common in our waters during the summer ; it is 

 very sluggish in its motions, and the surface of the body is usually 

 infested with numerous parasites. Dr. Binney had satisfied him- 

 self that these animals subsist on the Acalepha. He has fre- 

 quently found remains of the Medusae in their stomachs, and has 

 seen one captured while in the act of sucking in a large specimen 

 of one of these animals. Their slow movements, and inefficient, 

 jaws prevent them from pursuing a more active prey. 



Mr. Bryant stated, that, while off our coast during the past sum- 

 mer, he had sometimes seen ten or twelve in the course of a day. 



Professor Gray made some remarks on the Monograph 

 of Professor Choisy on the genus Cuscuta published in the 

 11 Mem. de la Soc. de Physique and d'Hist. Nat. de Ge- 

 neve."* 



With regard to the plants to which they attach themselves, Pro- 

 fessor Choisy says that they have never been found on those pos- 

 sessing acrid or poisonous juices. Dr. Gray has seen a species on 

 the Cherry Laurel, (Cerasus Caroliniana,) the poisonous princi- 

 ple of which is Prussic acid. Though most commonly met with 

 on the Compositre and Leguminosse, Professor Decandolle had met 

 with it in one instance only upon one of the Grasses ; but in this 

 country at least, one genus of Grasses, (Leersia,) is occasionaliv 

 infested by these parasites. Six of the species of this country 

 described by Dr. Engelman appear not to have fallen under Profes- 

 sor C's observation. Cuscuta Gronovii of Choisy is identical with 

 the C. vulgivaga of Engelman ; and his C. glomerata is Dr. E's yet 

 unpublished C. adpressa. 



Professor Gray also exhibited, under the microscope, specimens 

 of the papillae covering the achaena of the seeds of the genus Sene- 

 cio, which, when moistened, project from their extremities spiral 



