HYDROZOA, SCYPHOZOA, ACTINOZOA, VERMES WHITELEGGtE. 377 



evenly distributed ; they are generally under 2 mm. apart and 

 about 0*2 mm. in diameter. The dactylopores are about 0*1 mm. 

 in diameter, and pretty regularly arranged in cycles. 



The surface ridges are about (H mm. apart. 



Order SIPHON OPHOR A. 



FAMILY PHYSALID^. 

 PHYSALIA MEGALISTA, Lamk. 



Physalia megalista, Lamk., Anim. sans Vert., ii., 1816, p. 481 ; 

 Peron et Lesueur, Voy. de Descouvertes aux terres australes, 

 Atlas, 1807, pi. xx., fig. 1 ; Haeckel, Chall. Rep. Zool., xviii., 

 pp. 351 - 372. 



Numerous examples of this species were obtained by Mr. Hedley, 

 who also made a coloured sketch from a living specimen ; the 

 colours exhibited in the drawing, and by the specimens when re- 

 ceived, agree with examples of this species from the coast of New 

 South Wales. 



During the past five or six years I have paid special attention 

 to the PhysaUdce occurring on our coast ; two species have been 

 observed, i.e., Physalia megalista and P. utriculus.* They occur 

 nearly all the year round with favourable winds, such as N.E., 

 E., or S.E., occasionally in company, but more frequently only one 

 species is obtainable at a time. I have afc various times closely 

 examined hundreds of living individuals of both species, and can 

 readily separate the two by their colour alone. There are, how- 

 ever, other more important characters which clearly indicate that 

 they are specifically distinct. 



In Physalia megalista the crest is long in proportion to the rest 

 of the pneumatophore, whilst the anterior crestless portion is re- 

 markably short. The ventral group of cormidia are arranged in 

 well defined clusters, two anterior and three posterior to the main 

 tentacle. Each cormidium consists of a short broad pedicel 

 more or less transverse to the axis and a series of short branchlets 

 from which arise the ventral appendages: siphons, tentacles, pal- 

 pons, and gonodendria. 



The basal group of cormidia are separated from the ventral 

 by a very short space. They consist of five or six clusters of 

 small palpons, siphons, and frequently from one to three ten- 

 tacles in addition to that which subtends the terminal proto- 

 siphon. 



* Chun unites all the Pacific and Indian Ocean forms under the name 

 of Physalia utriculus. (See Zool. Anzieg., x., 1887, p. 658.) 



