514 On new Recent Pharetronid Sponges. 



Fiff.W. Sperm ball, X 1100; 11 «, spermatozoa, X 1100. 

 Fi(/. 12. Firm skeletal network : a, axial spicule ray, X 90. 

 Fig. 13. Strand of network showing- ray of quadriradiate surrounded by 

 fibrillar cement : «, axial spicule ray ; b, coment, X 525. 



Plate XIV. 



Min ch in ella lamellosa. 



Spicules, all magnified 525. Figs. 1-9 poral spiculea ; 

 figs. 10-16 oscular spicules. 



Fig. 1. Quadriradiate of poral chimney. 



Fig. 2. A larger example of the same. 



Fig. 3. Quadriradiate with long gastral and nearly equal basal rays; un- 

 paired ray spined. 



Fig. 4. Triradiate (poral). 



Figs. 5, 0. Tuning-fork spicules ; fig. 5 with extra prong. 



Fig, 7. Mouaxon from layer forming a pile on poral chimney. 



Fig. 8. Longer slenderer mouaxon from. upper end of poral chimney. 



Fig. 9. Spicule from fringe round upper end of poral chimney. 



Fig. 10. Oscular quadriradiate. 



Fig. 11. Fntto, with very short unpaired basal ray. 



Fig. 12. Triradiate (oscular) with long unpaired ray swollen towards 

 distal end. 



Figs. 13, 14. Triradiates with medium and very short unpaired rays. 



Fig. 15. Tuning-fork spicule. 



Fig. 16. Mouaxon, from layer forming a pile on surface of oscular 

 chimney. 



Plate XV. 



Minehinella lamellosa, figs. 1-9. Merlia normani, figs. 10-18. 



Fig. 1. M. lamellosa. Upper end of poral chimney of specimen A, 

 longitudinal section, X 90. 



Fig. 2. Longitudinal section of upper end of oseuleof specimen A, x 90. 



Fi(j. 3. Transverse section of oscular chimney, X 90. 



Fig. 4. Large quadriradiates and some triradiates slightly cemented, 

 from base of poral chimney, and showing transition-stage to 

 firm network forming body of sponge, x 150. 



Figs. 5-7. Stages of young quadriradiates not yet cemented, x 525, 



Fig. 8. Large monaxon, occurring in bard base of poral and oscular 

 chimney, X 525. 



Fig. 9. Strand of skeletal network showing development of iuca-iiig 

 cement, firstly a thin carpet, then stalagmites, the latter finally 

 immersed in cement matrix : a, axial spicule ray, X 525, 



Fig. 10. Merlia 7iormani, gen. et sp. n., incrusting rock : o., oscuLss. 

 Nat. size. 



Fig. 11. Surface enlarged, showing a pore in membrane covering each 

 polygonal area, X 45. 



Fig. 12. Vertical section of a surface '* honeycomb '' cell, showing mem- 

 branous roof supported by tufts of fine tyles, X 90. 



Fig. 13. Surface of macerated skeleton, with a tuning-fork spicule on 

 one of the floors : a, tubercle at end of vertical column ; 

 b, raphe ; c, horizontal floor. X 90. 



F\g.'\A. Vertical section : a, vertical column ; />, raphe ; c, floor. X 90, 



Fig. 15. Tyles, X 525. 



Fig. IG. llhaphides in dermal membrane, X 525. 



Fig. 17. Slender curved micro-rhaphides in derm«tl membrane, 



Fig, 18. Tuning-fork spicules, X 525, 



