PLATE XLVIII. 



Porpalia prunella, n. sp. (p. 58). 



I Ham. 



Fig. 1. The medusiform corm, seen from the superior or exumbrellar face. The 

 radiate pneumatocyst shines through the central part of the ex- 

 umbrella, which exhibits numerous radial ribs and rows of stigmata. 

 The margin of the umbrella is beset with glands and surrounded by 

 a corona of tentacles arranged in eight radial bunches, . . x 1 



Fig. 2. Lateral view of the same corm in profile. A deep subumbrellar circular 

 furrow separates the margin of the umbrella (w) from the multiple 

 corona of tentacles (t). Many tentacles are detached and their 

 insertions only visible (tu) ; iv, subumbrella ; ue, exumbrella. The 

 large central siphon (sa), with a long proboscis and octolobate mouth 

 (ss), is surrounded by a corona of eight peripheral smaller siphons 

 (sx) bearing numerous medusiform gonophores (g), . . . x 20 



Fig. 3. Vertical meridional section through the main axis of the same corm. 

 The central air-chainber (ph) of the campanulate pneumatocyst is 

 separated by the subspherical centradenia (tic) from the base of the 

 central siphon (sh) ; so, central mouth ; st, lamina gastrobasalis. Two 

 smaller sexual siphons (sx) bearing gouophores (g) are visible beyond 

 the corona of tentacles (t). The other characters as in fig. 2, . x 20 



Fig. 4. Apical view of the pneumatocyst (from the superior side), with radial 



marginal lobes expanded, . . . . . . x 10 



Fig. 5. Basal view of the pneumatocyst (from the inferior side), with numerous 



simple tracheae, . . . . . . . x 10 



Fig. 6. A radial segment of the pneumatocyst (fig. 5), from the inferior side. 



p?i, Central chamber ; pk, concentric chambers ; pt, simple tracheae, x 50 



Fig. 7. A radial segment of the centradenia, from the superior side, taken from 

 Porpita fungia (PI. XLV.). The numerous dentate radial laniellse, 

 which arise from the upper surface of the central gland, fit into 

 corresponding radial furrows between the crests arising from the 

 lower side of the pneumatocyst, . . . . . x 20 



Fig. 8. Eadial section through the middle portion of the pneumatocyst, 

 exhibiting three concentric air-chambers (pk). pg, Pneurnothyrse 

 (pori communicantcs) ; pe, stigmata ; pt, tracheae, . . . x 80 



