308 SUBANTARCTIC ISLANDS OF NEW ZEALAND. [Ilydromedusae. 



Some of these tentacles are smaller than others, but there seems to be no constant 

 regularity in their arrangement. One can recognise, however, that the perradial 

 bulbs are larger than the rest, and in a large individual there are about 48 others — 

 i.e., 12 in each quadrant bounded by the perradials. In such a specimen one can 

 distinguish three distinct sizes, which may be termed A, B, C, the last being the 

 smallest. There are three As, three Bs, and six Cs, as in the figure. The largest 

 are nearly as big as the perradials ; one of them is interradial in position, the two 

 others are subradial ; and generally there is a B between two As, and a C between 

 A and B. In smaller individuals there are fewer tentacles — as few as 24. There are 

 8 adradial statocysts (or marginal vesicles), situated between 2 tentacles of sizes B 

 and C. Each spherical statocyst is supported on a thickened cushion, which re- 

 sembles a tentacle-bulb. The outer surface is divided up into a number of hexagonal 

 or 23olygonal areas, the free ends of the transparent ectoderm cells. There are 4 to 

 6 statoliths, situated near and limited to the distal half of the interior of the vesicle ; 

 each is separated from its neighbour by a membrane (? tlie cell-membrane of the 

 refringent body). 



The manubrium is quite short — 2 mm. in length in the larger specimens. It 

 is quadrate at the base. The mouth when closed is cruciform, but when widely 

 opened is more or less circular, and its margin is very delicately folded (fig. 5). On 

 the inner surface of the interradial sides of the stomach are rows or groups of little 

 romided papillae, which are probably digestive glands. The 4 radial canals arise at 

 the base of this stomach or oral cavity as open grooves, which meet in the centre ; 

 each canal presents a iihort proximal region (about 1 mm. in length, measured fi'om 

 the angle of the manubrium), along which the endoderm is distinctly thicker than 

 in the distal portion (fig. 6). 



The festooned and undulating gonads hang down from nearly the entire length 

 of this distal region of the canal, each being (i mm. in length, and of considerable 

 height. 



Dirnensions. — From 10mm. to 20mm. in diameter; the larger ones about 5mm. 

 in height. 



Colour. — Transparent, colourless (in formol). 



Locality. — Auckland Islands : Norman's Inlet (Chiltcni). Campbell Island : Per- 

 severance Harbour (Chilton). 



Remarks. — The genus Phialella was created by Browne for a species, P. falk- 

 landica,* captured in Stanley Harbour. It differs from Tiaropsis, Agassiz. in the 

 fact that the statocysts are closed sacs, and in the absence of definite ocelli on the 

 tentacle-bulbs. 



The present species may possibly be identical with this, but the height of the 

 Falkland Island species is 11 mm. for a diameter of 17 mm.. and there are 60-70 

 tentacles. 



How far these features are of specific value is doubtful. It is known that in 

 this family the number of tentacles increases with age,^while the height may depend 

 on the mode of preservation. 



The hydroid is unkn(jwn, though presumably it bek)ngs to the Campanularians. 



* Browne, " A Preliminary Report on the Hydromedusae from the Falkland Islands," Ann. Mag. 

 Nat. Hist. (7), Lx, p. 282. 



