EXPLANATION OF PLATES. 



The figures on Plate IV, fig. 2, Plate VI, figs. 1,2, Plate VII, fig. 9, Plate XXI, figs. 

 1, 2, and Plate XXV, fig. 8, were drawn l.y Mr. .1. II. Wake. Plate XV, figs. 9, 10, 11, 

 were drawn by Mr. J. H. Kmertou. The other figures are all camera-lucida draw 

 ings by Mr. A. H. Verrill. 



PLATE LXXI. 



Fig. 1. Cardiomya f/lypta Bush, p. 810. Dorsal view of type specimen No. 35362; 

 X 10 diameters. 



2. Cuspidaria arciica (M. Sars) Dall, p. 803. Interior of a left valve from sta- 



tion 70; X about 3. Broken outline restored by lines of growth. 



3. Cardiomya gemma Verrill and Bush, p. 809. Dorsal view of specimen Xo. 



41456; x 10. 



4. The s:une. Interior of left valve of the same specimen; x about 13. 



5. Ciispidaria media Verrill and Bush, p. 800. Dorsal view of specimen No. 



49020; X 5. 



6. The same. Interior of left valve of type specimen No. 49018; X 5. 



7. Cuspidaria fraterna Verrill and Bush, p. 803. Dorsal view of specimen Xo. 



48962; X 5. 



8. The same. Interior of left valve of type specimen from station 892; x 5. 



9. Ciispidaria gJaciaUs (G. O. Sars) Dall, p. 800. Dorsal view of specimen No. 



49023; X 5. 



PLATE LXXII. 



Fig. 1. Cuspidaria undata Verrill, p. 798. Hinge of both valves of specimen No. 

 52517; x about 3. 



2. Halonympha si rid tell a Verrill and Bush, p. 810. Hinge of a right valve from 



station 2655 ; X 25. 



3. The same. Turned up to show anterior tooth ; x 25. 



4. Myornra ruyinosa (Jeffreys) Verrill and Bush, p. 811. Hinge of right valve 



of specimen Xo. 52544 ; X about 16. 



5. Cuspidaria rentricosa Verrill and Bush, p. 802. Hinge of a right valve Xo. 



52548; x 5. 



6. Cuspidaria rostrata (Spengler) Dull, p. 800. Hinge of both valves of speci- 



men Xo. 49067; X 5. 



7. Cuspidaria turgida Verrill and Bush, p. 799. Hinge of both valves of type 



specimen No. 78789; X about 6. 



PLATE LXXIII. 



Fig. 1. Cuspidaria subtorla (Sars), p. 806. Hinge of both valves of specimen Xo. 

 52545; X 9. 



2. Cardiomya perrostrata Dall, p. 809. Hinge of both valves of specimen No. 



48933; x 22. 



3. Cardiomya miiUicostata Verrill and Smith, p. 808. Hinge of both valves of 



specimen Xo. 48947; X 4i. 



4. Cardiomya abyssicola Verrill and Bush, p. 806. Hinge of two separate valves 



Xo. 78896; X 44. 



5. Cuspidaria glacialix (G. O. Sars) Dall, p. 800. Hinge of right valve of speci- 



men Xo. 49011; X -U. 



6. Cuspidaria mrdia Verrill and Bush, p. 80.). Hinge of both valves of type 



specimen Xo. 49018; X 9. 



