CONCHYLIA— D/THYi?^. xliii. 



2. subauriculata, depressa, striis rectis uniformibus. 

 flattlsh, with straight uniform strloe. 



48. AvicuLA. 

 1. Hirundo, caudd longitudine ala. 



the tail as long- as the wing. 



49. Pinna. 



1. ingens, arcuatim striata, posticd truncata recta. 



with curved striae, truncate and straight at the 

 hinder side. 



2. fragilis, arcuatim striata, postice producta rotundata. 



with curved striae, produced and rounded at the 

 hinder side. 



3. pectinata,. costis 16 confertis squamosis. 



with 16 close-set scaly ribs. 



4. papyracea, costis 9 remotis muticis. 



with 9 remote unarmed ribs. 



5. muricata, carnea, costis 7 concavo-spinosis. 



pale red, with 7 ribs armed with concave spines. 



50. Anomia. 



1. electrica, pellucida succinea. 



transparent and amber-colored. 



2. Ephippium, suborbicularis, margine undato. 



somewhat orbicular, undulate at the margin. 



3. Cepa, obovata planiuscula, intus rosea. 



oboval flattish, rosy on the inside. 



4. Squamula, suborbicularis Icsvis pellucida. 



somewhat orbicular smooth and transparent. 



