EXPLANATION OF THE PLATES. 



All figures made with the aid of a camera lucida except habit sketches. 



PLATE 14. 



Fig. 1. — Membianipora circumclutlirata Hincks. A few zooecia showing 

 sijines on the margin of the aperture (ap.), and the areolations (are.) be- 

 tween the zocpcia. X 50. 



Fig. 2. — M. circumclathrata. A single zooecium (zoe.) with its spines 

 and areolations, bearing an ooecium (oe.) at its distal extremity. The avi- 

 cularium (av.) of the distal zooecium perched on the summit of the ooecium. 

 X 50. 



Fig. 3. — Membranipora Jwrrida Hincks. A few zooecia showing both 

 stiff spines (st. sp.) and flexible spines (fix.sp.); also the elongated avicu- 

 larium below the aperture, and the ooecia (oe.). X 30. 



Fig. 4. — M. horrida. One of the large avicularia, the muscular portion 

 representing the transformed zooecium (soe.) and its contained polypide, the 

 mandible being the enlarged operculum (op.). X 30. 



Fig. 5." — ■Membranipora lacroixi Audouin. A few zooecia showing the 

 granular margin (mar.) and the triangular spaces (tri.spa.) below the aper- 

 ture. X 50. 



Fig. 6. — Aleinbraniporu occultata sp. uov. A few zooecia showing stiff 

 spines (st. sp.) and avicularia («i'.) below the aperture. X 30. 



Fig. 7. — M. occultata. A few zooecia showing both stiff and flexible 

 spines (fl.sp.), also the ooecia (oe.) hidden behind the calcareous wall of 

 the distal zooecium. X 30. 



Fig. 8. — M. occultata. One of the large spatulate avicularia. X 30. 



Fig. 9. — M. occidtata. The ooecium (oe.) drawn to a larger scale of 

 magnification to show its relation to the calcareous wall (cal. wa.) and to 

 the avicularium (av.) of the distal zooecium. X 70. 



