187 



House of Refuge, with an Appendix. Philadelphia, 1851. — From 

 James J. Barclay, Esq. 



The Plough, the Loom, and the Anvil. Vol. III. No. 9. March, 

 1851. Philadelphia. 8vo. — From J. S. Skinner, Esq., Editor. 



Mr. Lea made the following remarks on a communication 

 from Professor Agassiz to the Natural History Society of Bos- 

 ton: — 



In the last number, just published, of the Proceedings of the Boston 

 Society of Natural History, Prof. Agassiz states that he had been en- 

 gaged in the study of the soft parts of the American fresh water Mol- 

 luscs, with the object of "discovering some new characters on which 

 to base an accurate classification." Fie states that he had " found, 

 that in addition to the two muscular impressions in the shell usually 

 described, there are generally two or more produced by muscular 

 fibres springing from the foot, which impressions, in some species, 

 are confluent, in others more or less distinct." 



The existence of these muscular fibres was communicated by me 

 to this Society in November, 1827, and published in Vol. III. page 

 263, of the Transactions, new series. The paragraph is as follows: 

 "There cannot be a doubt that the two pairs of muscles which sup- 

 port the feet, and serve by their alternate action to give the animal 

 locomotion, are entirely distinct from the great anterior and posterior 

 muscles, which seem but to serve the purpose of closing the valves 

 opened by the elasticity of the ligament. The cicatrices of the mus- 

 cles of the foot, anteriorly, are placed under the great anterior cica- 

 trix ; posteriorly, over the great posterior cicatrix, and are sometimes 

 confluent with the great cicatrices, sometimes entirely distinct from 

 them." 



Again, Prof. Agassiz states that "other impressions exist, produced 

 by the gills, the palpi, and the dorsal gland." These were noticed 

 by me at the same time as "another set (dorsal) of attaching muscles 

 which seemed to have escaped attention." They are mentioned by 

 me as "making impressions (cicatrices) in the cavity of the valve be- 

 neath the beak-" They are stated as "supporting the mantle, bran- 

 chise," &c. In regard to the observation of Prof. Agassiz, that "these 

 impressions in some species are confluent, in others more or less dis- 

 tinct," I was, when I first observed this anatomical structure, so 

 much impressed with its importance, that I used it in descriptions of 

 the species made known in that paper, and have, I believe, used it 



