THE NAUTILUS. 89 



therefore becomes necessary to substitute a new generic name for 

 the molluscan Seutellina, and since the root of that word has become 

 associated with the Echinodermata, a change to something totally 

 different may be advisable. As a substitute, therefore, I otier the 

 term Phenacolepas, " a deceptive limpet." 



The synonyms are as follows : 



Scutella Broderip, P. Z. S. 1834, p. 47 (in part). 



Not Scutella Lamarck, An. s. Vert, iii, p. 7 (1816). 



Seutellina Gray, P. Z. S. 1847, p. 168, and of authors generally. 



Not Seutellina Agassiz, Monogr. d'Echinodermes, Second Monog. 

 des Scutelles, p. 98 (1841). 



DESTRUCTION OF ANODONTA CORPULENTA CPE. AT THOMPSON'S 

 LAKE, ILL. 



BY AV. S. STRODE, M. D., BERNADOTTE, ILL. 



Recently while on a collecting trij) to Thompson's Lake on the 

 Illinois River, I was greatly surprised at the immense number of 

 dead mussels that lined the shores from one end of this body of 

 water to the other. 



A windrow of them extended a little beyond the water's edge 

 clear around the lake a distance of not less than ten miles. 



Upon going on to the lake iu a boat I found that dead shells, with 

 the animal still in them, were also floating all over its surface. 

 There Avas absolutely thousands of them and it certainly amounted 

 to extinction of a very beautiful and interesting species, the Aiio- 

 donta corpulenta of Cooper. 



The other Anodonta, the suborbiculata of Say, for which this lake 

 is headquarters, did not seem to be affected and there were not more 

 dead ones to be seen than in previous years. 



I immediately set about to ascertain the cause of this wholesale 

 destruction of the corpulenta. 



On enquiring of Captain Schulte and other fishermen Avho owned 

 the lake, they had but one theory as to the cause, and that it Avas 

 the common northern bull-head catfish, Ammrus nebulosus L. S., 

 that was doing the mischief. 



They explained that this fish would attach his Avide mouth over 

 one end of the shell and suck until the muscular power of the mus- 



