EXPLANATION OF PLATE XXIX. 
Ficure 203.—Astarte undata, (p. 684;) somewhat reduced. 
204.—Astarte castanea, (p. 685 ;) natural size. 
205.—Astarte quadrans, (p. 685;) natural size. 
206.—Gouldia mactracea, (p. 685;) natural size. 
207.—The same, inside of one valve, enlarged. 
208.—Levicardium Mortoni, (p. 683;) natural size, with animal. 
209.—Cardium pinnulatum, (p. 683;) natural size. 
210.—Solenomya velum, (p. 688 ;) ‘natural size. 
211.—Cyclas dentata, (p. 686 ;) natural size. 
212.—Lucina filosa, (p. 686 ;) natural size. 
213.—Cryptodon Gouldii, (p. 686 ;) enlarged two diameters. 
214.—Cryptodon obesus, (p. 687 ;) enlarged three diameters. 
215.—Cyclocardia Novangliz, (p. 684;) natural size. 
216.—Cyclocardia borealis, (p. 683;) natural size. 
(Figures 203, 207, 214 were drawn by A. E. Verrill; 215 by E. S. Morse; the rest from Binney’s Gould, 
and mostly drawn by E.S. Morse.) 3 
