37 



In compliance with a special request, Mr. Putnam discoursed upon 

 the " Greenhead." So numerous are these flies upon the Ipswich and 

 Eowley marshes, so bloodthirsty their disposition, so fierce their 

 onset, so unforseen and overwhelming their attacks, that the citizens 

 of Rowley listened feelingly to a minute description of the green eyes, 

 of the bodily structure, and especially of the lance and blood-sucking 

 tube with which their inveterate foe tortures his victims. 



To indicate more exactly its character, Mr. P. spoke of the classifi- 

 cation of Dipterous insects, stating that this fly belonged to the same 

 family as the common horse-fly. In reply to a question, Mr. Putnam 

 also spoke of the bot-fly, its method of development in the stomach 

 of the horse, and its effect upon that animal. 



He concluded by exhibiting the skull and other parts of an Indian 

 skeleton, presented by Mr. WM. JOHNSON, and with the request that 

 the present or future owners of Indian relics would send them to the 

 cabinets of the Institute. 



Mr. ALPHEUS HYATT, continuing the description, commenced by Mr. 

 Putnam, of specimens collected by the dredging party, exhibited some 

 strips of eel-grass upon which were incrustations resembling groups 

 of dots united by delicate white lacework. In the openings of this 

 lacework lived minute animals which were beautiful objects when 

 viewed through the microscope. They are called polyzoa. Although 

 so minute and transparent, yet the whole living process can be seen 

 carried on in them as perfectly as in larger beings. Mr. Hyatt had 

 seen them manifest emotion in the irritation produced when one 

 would interfere with another's comfort. . From an enthusiastic de- 

 scription of these microscopic animals, the speaker passed to some 

 general remarks upon the lower forms of animal life, saying that 

 every animal has a head, but in the lower animals this head is gener- 

 ally at the point of its attachment. It is not the seat of the govern- 

 ing power, and has not a high development. Still it is now well 

 established that every animal has a head, or nervous centre. From 

 a study of these lower animals one cannot but be strongly impressed 

 with the unity of design shown by a similar plan of structure in all 

 grades of animal life. 



Mr. Hyatt also spoke of the deltas formed by the Merrimac, Ipswich 

 and Rowley rivers, and described the methods by which deltas are 

 formed. The probable depth of vegetable accumulations upon the 

 delta forming the Rowley marshes is about two feet. 



Mr. ALLEN W. DODGE having asked whether the clam had under- 

 gone any change since it was first known and used by man, Mr. 

 PUTNAM stated that the clamshells in the ancient shellheaps were 

 heavier than those upon clams now living. This, perhaps, indicated a 

 deterioration and a possible future extinction of the clam. 



