PLATE XLIII. 



Armenista sigmoides, n. sp. (p. 84). 



Diam. 

 Fig. 1. Apical view of the conn (from above). The diagonal crest of the pneumatophore divides the 

 exumbrella into an antero-dextral and a postero-sinistral half. The limb of the umbrella is 

 octolobate, ........... nat. size 



Fig. 2. Basal view of the corni (from below). The large sterile central siphon is surrounded by a 



corona of numerous small sexual siphons, and these by a double corona of filiform tentacles, nat. size 



Fig. 3. Half lateral, half superior view of the corm. Numerous filiform tentacles are prominent 

 beyond the limb of the umbrella. The vertical diagonal crest of the pneumatophore exhibits 

 the branched canals of the exumbrella, ....... nat. size 



Fig. 4. Frontal section through the corm (or vertical transverse section), ph, Central chamber of the 

 pneumatocyst (pf); ce, canals of the umbrella; uu, limbus umbrella;; us, glands of the 

 umbrella margin; uc, centradenia ; uh, hepatic vessels; tin, renal vessels; t, tentacles; <js, 

 gonostyles (sexual siphons) ; g, gonophores ; sa, sterile central siphon ; sf, longitudinal folds 

 of its inside ; so, the octolobate mouth, . . . . . . . x 4 



Fig. 5. Pneumatocyst of a young corm, seen from above. Concentric ring-chambers with their pores 



of communication (pneumothyra;, pg) ; pe, their external openings (stigmata), . . x 2 



Fig. G. Central part of the pneumatocyst of a young corm, seen from below, highly magnified. The 

 central chamber (ph) is confluent with eight radial chambers (pq), each of which bears below 

 a branched trachea. The surrounding concentric ring-chambers ( ph) are connected by pores 

 of communication (pneumothyrse, pg), . . . . . . . x 20 



Fig. 7. Basal view of the isolated centradenia (uc) and the central siphon (sa), from below, cm, 



Gastro-canal system of the subumbrella ; so, mouth, . . . . . x 2 



Fig. 8. A single gonostyle or sexual siphon, gs, Its stomach ; g, gonophores ; leu, cnidonodes ; so, 



mouth, . . . . . . . . . . x 20 



Fig. 9. A medusiform gonophore, detached from the stem (Discom itra), highly magnified, w, Subum- 

 brella ; or, radial canals accompanied by yellow cells (xanthellse); t, rudimentary tentacles ; 

 s, the incipient manubrium, . . . . . . . x 100 



Fig. 10. A branched trachea of the' pneumatocyst. 



