45 



in all the ponds, and seem all of the same species ; I have not ventured to 

 give the specific name; probably they are the Jluviatilis ; they are hardly 

 thick enough for the implicata. I could not procure good specimens, they 

 are fragile, and on the shores are found much broken ; in the Fall, when the 

 waters are low, specimens alive may be procured. 



I send you also some specimens from the Merrimack River ; my range 

 has been about five miles on the Haverhill side, — say three above the railroad 

 and two below. These river shells are also " Musk-rat shells," but most of 

 them very fair ; they wer j found under bushes and covered with mud and 

 sand, and not injured by the sun. 



What I send may not be wanted by the Institute for Cabinet specimens, 

 but they may serve as a hint to the society to engage persons in the other 

 towns of Essex County to "go and do likewise," which plan, well carried 

 out, would give you a complete account of all the Naiades in the County. 

 I should like to be engaged in making such an interesting collection. I have 

 my eye on the ponds in Bradford, and the Bradford shore of the river, and 

 it is not impossible that, after a while, I may be able to forward another box. 



Some of the specimens now sent may do for the cabinet, if wanted; 

 especially the U. radiatus, and the rayed specimens of U. complanatus. I 

 would wash the outside with a sponge dipped in muriatic acid, very much 

 diluted, and when drj' put on the slightest possible coat of clear varnish with 

 a sponge ; the rays mil then show distinctly. 



Catalogue of Shells found in the ponds of Haverhill, Mass., and in the Mer- 

 rimack River near that Town. 



In Kenoza^ Lake. 300 Acres. Unio 'complanatus 'Solander ; Unio 

 radiatus Barnes ; Unio nasutus Say ^ Anodon sp. ? ; Physa hererostropha Say. 



In RoDNi) PcJtsid. 80 Acres. Utiio complanatus ; Unio radiatus; Unio 

 nasutus ; Anodon sp.1 



In Plug Pond. 70 Acres. Unio complanatus; Unio radiatus; Ano- 

 don sp. f 



I have n»vgr found U. nasutus in-this pond. ^ 



In Creek Pond. 300 Acres. Unio complanatus ; Unio radiatus ; Unio 

 nasutus; Anodon sp.? _,, 



In Merrimack River. Unio cariosus Say; Unto complanatus Solan- 

 der ; Unio radiatus Barnes ; Alasmodon uhdylatd Say. 



In my searches recently I found no TJ. radiatus in the river, but a few 

 years since I found numbers of them ; had none on hand to put into the 

 box. 



The Alasmodon undulata is a very rare shell in the river at this locality. 

 I was fortunate in finding one whole specimen and a single valve to forward 

 with the others. I never found but four specimens here. Three years ago 

 I picked up two very fair ones. 



I am uncertain about Anodnns in the river. I have not seen one near 

 the river this season. I have examined among all the shells found in my 

 range and have not seen a shell or a fragment of a shell of that genus. 

 Some years since I collected shells in the river, but I have no list of them, 

 and cannot say whether Anodonta was among them or not. 



Among tlie quantities of Unio complanatus found on the shores of the 

 ponds I have not seen a rayed specimen. All of this variety sent in the 

 box were from a sandy point, from a mile and a half to two miles below Ha- 

 verhill, on the shore of the river. 



All the shells in the box appeared to have been dropped by the Musk- 

 rats a good while since, as no animal matter was found on them." 

 Very respectfully yours, 



John Baktlett. 



