300 Dr. F. Briiggemann on Sto)i7/ Corals. 



J-'iff. 2. Aphrocallistes Bocagei. Two nodes of the network, with two sex- 

 radiate oasts, eaeli with one ray prolonged to form the interior 



of one of the long spines of the interior of the netted tube 



(Xl40). 

 Fig. 3. Capitate termination of a spieular cast in the fibre of D. suh- 



glohosus (X435). 

 Fig. 4. Fanra rlensa. A node of the network, exhibiting casts of three 



imbedded spicules ( X 104). 

 Fig. 5. Jfgdloiiciua Sicboldii. Cut end of a lengtli of the anchoring 



spicule, with the lamellar structure revealed by solution (^ X 104). 

 F'gs. 6 to 9. Geodia arabica. Globo-stellates in various stages of solution : 



/(, hilum ; /•, radiate structure ; c, central cavity ; s, contained 



air-bubble (X 140). 

 Figs. 10 Si. 11. rachi/DiatismaJo/mstouia. Globo-stellates : jw, hemispherical 



excavations ( x 140). 

 Figs. 12 & 18. Geodia arabica. Spines of a globo-stellate separated by 



solution: fig. 1:2, seen in elevation; fig. 13, in plan (X435). 

 Fig. 14. P. Johnston ia. Globo-stellate :/, thin structm-eless external film 



of silica, separated from the rest of the spicide within it {X 140). 

 Fig. 15. Hemispherical excavations on the exterior of an acerate spicule 



of Geodia arabica : a. one showing the circular outcrop of the 



concentric lamelliB round its walls (xl40). 

 Figs. 16 & 17. Ends of cvliiidrical spicules of Fachgmatis7na Johnstoiiia 



(:x43o). 

 Fig. 18. Abnormal structure, showing two spicules of P. Johnstoma an- 



kvlosed together ( x 140). 

 Fig. 10. T^rac/n/a, sp. Acuate spicule : a, originally pointed end ; b, 



rounded end (^x43o). 



XXXVII. — Notes oil Stoni/ Corah in the Collection of the 

 British Museum. By Dr. F. Bruggemann. 



III. A Revision of the Recent Solitary Mussace^. 



Of the above-named group, wliicli is equivalent to the Litho- 

 phylliacSes simples of Milne-Echvards and Haime, there 

 appear to exist at least four genera comprising living species. 

 They may be tabulated in the following manner : — 



A. Without a distinct epitheca 1. Scolymia. 



B. With an epitheca. 



a. Edges of the larger septa roughly lacero- 

 dentate, the outermost teeth the 

 strongest 2. Cyn.\rix.\. 



h. Edges of the septa equally dentate. 



1. Columella large, spongious 3. Antillia. 



2. Columella small, trabecular 4. Homophyllia. 



Taking other characters into view, another arrangement can 

 bj made : — 



