620 SAMPSON. [Vol. XI. 



described by Schiff for muscles that otherwise appear to corre- 

 spond in position with those figured by him. For these reasons 

 I shall not attempt to compare, muscle by muscle, the two 

 descriptions with the present account. The description by 

 Schiff appears to represent more nearly than Middendorff's 

 the condition in the forms that I have studied. 



Both Middendorff and Schiff speak of muscles that are 

 attached by both ends to the same cartilage, but I have been 

 unable to find such muscles, and presume from comparison of 

 the drawings, that the muscles from the radula sheath to the 

 cartilage {msi or mso) are those referred to. The muscles of 

 these groups appear to be attached anteriorly to the cartilage, 

 when seen from the dorsal side ; but the lateral projection 

 of the radula sheath, dorsal to the cartilage, produces this 

 effect, and in dissections, as well as in sections, the anterior 

 attachments are seen to be on the sheath. 



Both authors have discussed at some length the functions of 

 the muscles, and Middendorff briefly describes some of the 

 muscles of the head region. 



Germantown, October, 1894. 



