EXPLANATION OP PLATES. 145 



PLATE 12. 



Fig. 1. Ophiotrema gracilis, upper face. X4. 



2. Ophiotrema gracilis, under face. X5.5. 



3. Ophiotrema alberti, upper face. X3. 



4. Ophiotrema alberti, under face. X3. 



5. Ophwmitrella porrecta, upper face. X6. 



6. Ophiomitrella porrecta, under face. X6. 



PLATE 13. 



Fig. 1. Ophiacantha (Ophiotreta) affinis, under face. X4. 



2. Ophiacantha (Ophwtreta) affinis, upper face. X4. 



3. Ophiacantha (Ophwtreta) a/mis, under face of another specimen. X5. 



4. Ophiomitrella Ixvipellis, upper face. X9. 



5. Ophwmitrella Ixvipellis, under face. X9. 



6. Ophiacantha vepratica, upper face. X5. 



PLATE 14. 



Fig. 1. Ophiochondrus granulatus, under face. X7. 



2. Ophiochondrus armatus, upper face. X8. 



3. Ophiochondrus armatus, under face. X8. 



4. Ophiochondrus granulatus, upper face of a small specimen. X6. 



5. Ophiochondrus granulatus, upper face of a larger specimen, the under face of which is illustrated 



in fig. 1. X6. 



6. Ophiochondrus armalus, more enlarged under face of the specimen illustrated in fig. 3. X7. 



7. Sigsbeia conifera, upper face. X8. 



PLATE 15. 



Fig. 1. Ophiomitrella americana, upper face. X6. 



2. Ophwmitrella americana, under face. X6. 



3. Ophiacantha anomala, upper face of a fairly large specimen. X8. 



4. Ophiacantha anomala, under face of the same. X4. 



5. Ophiacantha anomala, under face of a young specimen. X8. 



6. Ophioleptoplax atlantica, upper face. X7. 



7. Ophioleptoplax atlantica, under face. X7. 



PLATE 16. 



Fig. 1. Ophiothrix convoluta, upper face. X4. 



2. Ophiobyrsella quadrispinosa, upper face. X1.7. 



3. Ophiobyrsclla quadrispinosa, under face. XL7. 



4. Ophiologimus secundus, upper tace. X10. 



5. Ophiologimus secundus, under face. X12. 



6. Ophiothrix convoluta, upper face of the disk, more enlarged than in fig. 1. X7.5. 



PLATE 17. 



Fig. 1. Astrochema elongatum, upper face. X3. 



2. Astrochema elongatum, under face of the whole animal, slightly reduced. 



3. Astrochema elongatum, under face, more enlarged. X3. 



4. Sigsbeia sexradiata, upper face. Xll. 



5. Sigsbeia sexradiata, under face. Xll. 



6. Sigsbeia conifera, under face. X8. 



