1550 



THE VOYAGE OF H.M.S. CHALLENGER. 



Tlie Central Capsule of the Cannorrhapbida seems to possess the same shape in the 

 three subfamilies, and to agree in general with that of the Aulacanthida. In a living 

 specimen of Dictyocha stapedia, which I observed at Ceylon (PI. 101, fig. 10), the 

 three openings of the Tpjpylea were distinct ; the radiate operculum of the astropyle 

 (on the oral pole) was surrounded by the granules of the dark phseodium, whilst on 

 the opposite aboral side, two parapylse or conical secondary openings were visible. The 

 voluminous spherical calymma (about four times as broad as the central capsule) contained 

 numerous large alveoles (as in Aulosj^hcera) and its surface was protected by numerous 

 pdeated pieces of the skeleton ; the basal ring of the latter was placed tangentially 

 in the sj^herical surface of the calymma, their apical spine being directed outwards 

 The pseudopodia, arising from the central capsule and forming a network between the 

 alveoles of the calymma, radiated outwards in great number from its surface (PL 101, 

 fig. 10). 



The propagation by self-division seems to be very frequent in the Cannorrhapbida. 

 I frequently found two equal central capsules in one calymma, as in the first observed 

 sj^ecies, Cannohelos cavispicula, and in Cannorrhaphis spinulosa (PL 101, fig. 3), 

 sometimes also in Dictyocha and Distephanus. As already mentioned, Catinulus 

 constantly exhibited four central capsules united in each calymma. 



Synopsis of the Genera of Cannorrhaphida. 



I. Subfamily 



Canaobelida. 

 Pieces of the skeleton 

 cylindrical or spindle- 

 shaped tangential 

 tubules. 



Tubules simple, smooth, 

 Tubules spiny or branched, 



. 658. Cannohelos. 

 . 659. Cannorrliaphu. 



IL Subfamily 



Catiuulida. 

 Pieces of the skeleton - 

 hemispherical or cap- 

 shaped, solid. 



Caps or hemispherical pieces of the skeleton solid, with radiate 

 margin and circular opening, .... 



660. Catinulus. 



III. Subfamily 



Dictyochida. 



Pieces of the skeleton 

 either simple rmgs 

 or pileated or pyra- 

 midal bodies, com- 

 posed of thin hoUow 

 rods and reticular 

 meshes. 



Flinty pieces simple or 

 arched rings, not trun- 

 cated pyramids, with a - 

 basal ring, but without 

 apical ring. 



Flinty pieces of the skeleton 

 resembling a truncated 

 pyramid, with an upper ■; 

 smaller apical ring, and 

 a lower larger basal ring. 



Basal ring simple, not arched 

 or fenestrated. 



Basal ring fenestrated, with 

 two or more arches, vaulted 

 over one side. 



Apical ring simple, not fenes- 

 trated (one girdle of meshes 

 on each piece), 



Apical ring fenestrated (two 

 girdles of meshes on each 

 piece), 



661. Mesocena. 



662. Didyoclia. 



663. Diste2)7iamcs. 



664. Cannopilus. 



