— lOlB — 
1. valvîs sculptura iso- 
morpha 
hh Sculptura heteromorpha 
1. Val vis absque denticulis subraargi- 
nalibus Ò.Aslerolampreae 
2. valvis denticulis submarginalibus 
praeditis 6. Heliopelteae 
A A' Valvis oblongis. 
aa Frustula cingulo et valvis symmetrica 
|a vittis tran- 
sverxis tan- 
tum obte- 
xtis . . 7. Meridioneae 
valvis striis 
p u ne tatis 
transversis 
medio inter- 
ruptis, dis- 
sep ime ntis 
rudimenta- 
riis internis 
instructis. 8. Licmophoreae 
2. valvis scluptura saepius heteremor- 
pha, idest pinnatis aut costatis plus 
minusve late area mediana interrup- 
tis, et seriatim punctatis, septis iiite- 
rioribus destitutis 9. Sitrirelleae 
hh Frustula incurvata (Dorsiveiitralia) 
cingulo symmetrico, et valvis asyme- 
trico-recurvis 10 Eunotieae 
ce Frustula cingulo valvisque symmetrica 
1. valvis carinato-punctatis . ... 11 Nitzschieae 
2. valviscarina et septis interioribusca- 
rentibus 12 Frag ilarieae 
3. valvis dissepimentis internis perfora- 
tis instructis 13 Tahellarieae 
