Plate 13. 



Fig. 1. Thenea lamelUformis. Spirasters ; x 600. 



" 2. Thenea fe?iestrata 0. 8chm. From a photograph ; from above ; \. 



3. " " " Spirasters ; x 600. 



4. " " ■ " Protriaene; x 100. 



" 5. Thenea pyriformls. From a photograph ; from the side ; \. 



" 6. Thenea fenestrata 0. Schm. Protriaene; x 100. 



" 7. " " " Dichotriaene, modified toward protriaene ; x 100. 



" 8. Thenea pyriformls. From a photograph ; from above ; \. 



" 9. Thenea fenestrata 0. ^ohm. From a photograph ; from the side ; \. 



" 10. Thenea -pyriformls. Parench3'mal microscleres ; x 600. 



" 11. " " Microscleres of dermal membrane ; x 600. 



" 12. Poeclllastra trlcornis. Annulated microxea; x 150. 



" 13. " " Triaene with reduced rhabdome ; from the side; x 30. 



" 14. " " Microxea, nearly smooth; x 400. 



