230 CEYLON PEARL OYSTER REPORT. 



Heteropegma, PoleSjaeff. 



Amphoriscidae with elongated flagellate chambers arranged radially around the 

 central gastral cavity. With a vestigial tuhar skeleton of minute radiates. 

 With a very thick dermal cortex, composed principally of triradiate spicides. 



Heteropegma nodus-gordii, Polejaeff (77). 



This remarkable and well-characterised species is represented in the collection by a 

 single good-sized specimen, which agrees very closely with the types described by 

 Polejaeff in 1883 from Australia (Cape York) and the Bermudas. The only other 

 species known is the very closely related //. latitubulata from near Port Phillip 

 Heads (80), so that the genus is apparently a characteristic Australian one, and the 

 discovery of H. nodus-gordii (the Northern Australian form) at Ceylon affords 

 another good example of the close relationship between the Ceylonese and Australian 

 Sponge-Fauna. The anatomy of this species has been figured both by Polejaeff (77) 

 and by myself (78). 



R.N. 155 (Ceylon seas). 



LIST OF THE CEYLON SPONGE-FAUNA 



so far as at present known ; showing the classification adopted and the geographical 

 distribution of those species which have been recorded from localities beyond the 

 Ceylon ai*ea. The species marked H occur in Professor Herdman's collection ; those 

 marked D are doubtful* : 



Class-. NON-CALCAREA. G. Stceba (Samus) simplex (Carter, 4)t, Temate 



Order: Myxospongida. ( 87 )- 



H 7. Stceba extensa, n. sp. 



8. Triptolemus (Samus) parasiticus (Carter, 4).f 



9. Nethea (Tisiphonia) nana (Carter, 4).t 

 Order: Tetraxonida. 10. Sphinctrella 1 (Tisiplumia) annulata (Carter, 



Grade; Tetractinellida. 4).t 



Sob-order : Homosclerophora. Family : Stellettidse. 



Family : Plakinidae. n. Myriastra (Stelletta) crassicula (Carter, 5).t 



H 3. DeD-citcpsis ceylonica, n. gen. et sp. H 12. ,, clavosa (Ridley). Off north coast of 



H 1. Hexadella indica, n. sp. 



D 2. Halisarca (?) ruhitmgens, Carter (5) 



Sub-order : Astrophora. 



Australia; Philippine Islands; Amboyna (83) ; 



Ternate (87); Coast of Cochin China (86). 

 Family : Pachas trellidse. H 13 _ Myriastra tethyopsis (Carter). 



H 4. Plakinastrella intermedia, n. sp. 14. Pilochrota ceylonica, Sollas (15). 



H 5. ,, schulzei, n. sp. H 15. haeckeli, Sollas. Philippine Islands. 



* Iu compiling this list no notice has been taken of varietal distinctions. It may be noted that the 

 sponges described by me in my paper on " The Sponge-Fauna of Madras " (2) all came from the Gulf of 

 Manaar (vide Thurston, 99). t Fide Sollas (15). 



