EXPI.ANATION OF PLATE VII. 
Figs, i, 2. — Forms of Dichelaspis tridens. 
,, 3 . — Dichelaspis hathynomi (typical form). 
,, 4 — Z). hathynomi var. perfidiosa. 
, 5 — 7. — Pœcilasma minutum. Figure 5 represents an old and fig. 6 a 3^oung 
individual. 
, , 8. — Carina of Pœcilasma kæmpferi subsp. duhia from the Gulf of Manaar. 
,, 9, ga . — Heteralepas nicobarica, sp. nov. 
,, 10, loa, 10b . — Valves of Oxynaspis celata subsp. indica — 
Fig. 10. — Scutum and tergum (external surface). 
,, loa. — Scutiun of another individual (internal surface). 
,, 10Ô. — Carina. 
