1910.] FROM CTIRTSTMAS ISLAXU. 835 



Plumularia sp. {laajalocepluda Alhnaii, iifr.). 



Growing oil the base of a stem of Halt com aria hums, var. laxa, 

 were two simple stems of a Flumalaria which remains uu- 

 ideiitifieth Most of the hydroclades have disappeared, but sufficient 

 remains to show that the trophosome is akin in structure and 

 relative proportions to that of P. inegalocepliala Alhnan, found on 

 the shoi'Bs of the western Atlantic and eastern Paciiic Oceans. 

 From this they appear to diflter only in their simple habit and 

 small size, and in lacking that sai'cotheca which occurs on the 

 stem internodes, immediately proximal to the hydroclade-bearing 

 process. 



Dimensions : — 



Stem, length 1) mm. 



Stem internode, length ()*35-U"49 mm. 



diameter 0-039-0-084 mm. 



Hydrothecate internode, length 0*31 mm. 



„ „ diameter O-Ql 9-0-027 mm. 



Basal athecate internode, length 0' 1 4-0" 1 9 m m . 



Hydrotheca, depth 0"045 mm. 



„ diameter at mouth 0-048-0-051 nun. 



Locality. Flying Fish Cove, 46 fathoms. 



Halicornaria hians Busk, var. laxa, nov. 



This is the species most abundantly represented in tlio col- 

 lection. The largest colony is 12 cm. in height, and the uiinute 

 characters of the hydrothecje.agi'ee closely with Bale's* diagnosis 

 except that the mesial sarcotheca, in overtopping the hydrotlieca- 

 wall for some distance, approaches the condition of that described 

 by Stechowf. The ultimate portion lies, however, at a slioht 

 angle to the course of the main portion of the sarcotheca. 



There are difierences in habit, however, which distinguish 

 this variety. The colonies are delicate and fine in appearance ; 

 and the stem is thin and shows no traces of nodal consti-ictions. 

 The hydroclades, which are of the unusual length of 22 mm. 

 (twice as long as those recorded by Stechow), are alternate, and 

 are wide apart, a space of 2 mm. separating successive individuals 

 on the same side of the stem. They are divided into long inter- 

 nodes, on the upper portion of which the hydrotliecas are set. 

 In this respect, and on account of the greater deptli (as compared 

 with Bale's and Stechow's figures), and more erect posture of the 

 hydrothecaj (the axes of which are inclined to that of the hydro- 

 clade at an angle of al)out 40°, instead of 55^), and of the "-reater 

 elevation of the intrathecal septum above the floor of the hydro- 

 theca, these specimens resemble var. profanda, from the 

 AndamansJ. 



* Bale, Cat. Australian llvilvoid Zoopli., 1881. p. 170. 



t Steclunv, Abh. K. Bayer. Akad. Wissens., Suppl.-vol. i. 3, 1909, p. 101, pi. vi. 

 fisi'. 16. 

 't Ann. Mag-. Nat. Hist. (8) vol. iii. 1909, p. 528. 



