169 HYDROIDA. I'-AI.E. 



the first place it is a peculiar circumstance, not noticed by 



All man, that they are inside the hydrothecae. Then they are 



appendages of the hydrotheca itself, having no apparent con- 



nection with the hydrocaulus, as sarcothecas have, and I have 



been unable to detect any aperture except the distal one, so that 



even assuming that the stem of a sarcostyle entered the 



hydrotheca thrcmgh the same orifice as the hydranth, (a most 



improbable theory), it would still have no means of entering 



the cavity of the supposed sarcotheca Every sarcotbeca, like 



every hydrotheca, must have at least two orifices, one for the 



protrusion of the contained zooid, the other for connection with 



the hydrocaulus, and the fact of the latter being absent in this 



instance seems to negative the theory of the sarcothecal function 



of these receptacles. They are exactly like flat pockets attached 



to the hydrotheca, and they lie so close to it, and enclose such an 



extremely narrow space that it is difficult to imagine that a 



sai'costyle could occupy a cavity so contracted. 



The habit is similar to that of the "Challenger" form, but 

 the stem seems rather more slender and the pinnae shorter and 

 less regular. Sometimes for a certain distance they may be 

 regularly arranged, in which case they are alternate, with two 

 pairs of hydrotheca? between evei-y two, but for the most part 

 they are more irregular, and often several follow in succession 011 

 the same side. The longest specimen which I measured was 

 about seven inches in length, bare for about four inches up, and 

 the remainder with a regular series of branches all on one side. 

 But the cladophores remaining showed that the lower branches 

 had been bi serial. 



The branches may be without nodes, or may have one or two 

 short internodes at the ends, each supporting a pair or two pairs 

 of hydrothecaa. There does not seem to be any tendency to the 

 production of secondary branches, as none were found in the 

 colonies examined. 



The gonangia are unusually large (about 2'8 mm. long and 

 1'18 mm. in diameter), and the circlet of minute denticles which 

 are found in the neck of many species is here represented by 

 much larger irregular processes. 



.Great Australian Bight, Long. 126 45' E, 190-320 

 fathoms : Long 130 40 ' E, 160 fathoms. 



