1010.] FltCM MERGL'I AnCIilPELAGO. 815 



Dimensions : — 



Hydrotlieca, length 0-7-1-12 mm. 



„ diameter ^ 0-10-0-14 mm. 



Length of flaps of operculum 011-0-13mm. 



Localities. St. 1, east of Tavoy Lsland and Port Owen, 4 to 12 

 fathoms, sand and broken shells, and muil ; rare hydi-otheca; on 

 Thyroscyplms vitiensis. St. 3, French Bay, King Island, and 

 south end of Iron Island, 3 to 8 fathoms, mud and rock, or sand ; 

 very rare, on Thyroscyphus vitiensis. 



Famil}- L A F o E I D .E. 

 LafoEa serrata Clarke, 1 879. 



A widely distributed, but moderately i-are species. Repeated 

 regeneration of the hydranth had furnished one hydrotlieca (from 

 St. 22) with the exceptionally large number of eleven successive 

 inai'gins. 



Localities. St. 1, east of Tavoy Island and Port Owen, 4 to 12 

 fathoms, sand and broken shells, and mud ; fairly conmion, on 

 Idia pi-istis. St. 9, between Bentinck Island and Courts Island. 

 12 to 26 fathom.s, sand and shell; very rare, on Thyroscyphus 

 vitiensis. Stt. 15 and 16, Ravenshaw Island, Sir John Malcolm 

 Island, and Alligator Rock, 5 to 18 fathoms, rock and .sand, or 

 rock and mud ; rare, on Idia pristis. St. 22, Hastings Harbour, 

 shore to 20 fathoms, rock and sand ; fairly common, on Thyro- 

 scyphus vitiensis and Idia pristis. St. 23, Five Islands, 8 to 12 

 fathoms, rock and sand, and mud ; rare, on Eiidemlrium attenna- 

 iuml St. 25, Gregory Grouji and Crichton Island, 4 to 14 

 fathoms, stones and broken shells, and rock ; i-are, on Idia pristis. 

 St. 35, between Warden Island, Howe Island, and Lyall Island, 

 15 to 20 fathoms, lock and sand ; rare, on Idia pristis. 



LAFoiJA VExrsTA AUman (?), 1877. (Plate LXXVI. figs. 5 A 6.) 



Various Hydroids have associated with them a small form 

 which I refer, with a query, to this species. 



The trophosome consists of a creeping hydrorhiza from which 

 spring small c\'lindrical hydrotheciP, set on stout but variable 

 .stalks, and zoned by numerous, well-deKned, and regular corru- 

 gations. These decrease in distiuctne.ss towards the base of the 

 hydrotheea. The margin of the hydrotlieca is everted, .and the 

 stalk bears no regul.ar rings. A markeil and distinctive character 

 exists in the colour of the peiisarc which jiossesses a brownish- 

 smoke tint, .slightly varinble in cleiisity. An exceedingly delic.iti* 

 membrane forms the floor of the iiyilrotliec;i. 



The hydranth is cylindricid and minute, funiislied with a 

 hemispherical l\vpostouie, surrounded by tentacles v;iiying in 

 number fi-om nine to eleven. The tentacles ati<l body of the 

 hydranth have a granular appearance owing to the presence 

 of scattered nematoc3'.sts, which do not seem, even in the tent.'icles, 



53* 



[17J 



