Further Notes on Australian Hydroids. 103 



The specimens, of which there were very few, only reached 

 about one-fifth of an inch in height, but were doubtless immature. 

 The perisarc of the lower portions was rather thick. 



SyNTHECIUM PATULUiM, Busk. 



Specimens about two inches in height, with several of the 

 pinn?e anastomosing. Some of the hydrotheca3 are much stouter 

 and less curved than usual, with the margin more deeply sinuated 

 at the sides, while the portions of the internode outside of the 

 hydrothecse are correspondingly diminished ; the hydrothecse thus 

 occupy almost the whole internode. These modified internodes 

 are mixed on the same pinna with the normal form. 



Mouth of Snowy River (Dr. MacGrillivray). 



Thuiaria lata. Bale. 

 (Plate IV., fig. 1.) 



Gonothecifi borne two or three on a pinna, springing from 

 between the two series of hydrothecse, very large (about |^-inch 

 long), gradually tapering downward, thickest part a little below 

 the summit ; presenting, as seen in side view, a dorsal and a 

 ventral aspect, the former regularly undulated most of its length, 

 the latter smooth ; summit concave and oblique, more elevated 

 at the back than in front. 



Port Phillip Bay (Mr. J. B. Wilson). 



(The gonothecse of this species have not hitherto been described). 



Thuiaria fenestrata, Bale. 

 (Plate IV., fig. 2.) 



Port Phillip Bay (Dr. Macdillivray). 



The gonothecae are more nearly globular than those of any 

 other species known to me. The sketch of one of them by 

 Mr. Busk, which I copied in the " Catalogue of the Australian 

 Hydroid Zoophytes," and from which I took the description, is 

 evidently erroneous, which may possibly be due to some other 

 species having been mixed with the material. The description 

 in the " Voyage of the Rattlesnake " did not mention the gono- 

 some. 



