30 i;i»\v.\i;i> T. r.RowNi;. 



The ' Southoru Cross ' collection contains three specimens, taken at Cape Ailare. 

 The largest is in a mutilated conilition, having a clean-cut hole through the centre 

 of the umhrella. The stonuich and mouth Imve completely disappeared, autl so also 

 have the proximal ends of the gonads, but the margin of the umhrclla is in good 

 condition. The two other specimens are intermediate stages in l»ad condition. 



The ' Discovery ' collc(;tion al.so coutaius a mutilated specimen, which was taken 

 in McMurdo Scjund on 27th Manth, 1903, through one of the holes in the ice. 



Description of the Adult. — Umbrella slightly convex, and thick, about four times 

 as broad as high. Velum broad. Four radial canals with sinuous margins in the 

 gonadal regions, l»ut without conspicuous lateral diverticula. Gonads large and broad, 

 arranged in lateral and transverse folds, and extending over nearly the whole length 

 of the radial canals. Tcntailes long and slender, about 300, with a reddish pigment 

 in the endoderm, and with laterally compressed basal bulbs. Onv long dub-.shaped 

 cordylus between every two tentacles. 



Size. — Umbrella up to 60 mm. in diameter. 



Notes on the Specimens. — The ' Discovery ' specimen shows that the gonads extend 

 from the base of the stomach nearly to the circular canal. They arc arranged in a 

 series of lateral folds, along l)oth sides of the radial canals, and form a do.scd tube. 

 There is no evidence of a mouth extending over and along the gonads, a character 

 which distinguishes Staurophora from Ptycliogena. The radial cjinals of Ptychocfena 

 aiitarctica have not the conspicuous lateral diverticula of /-*. lactea. In the proximal 

 part of the canals there about two very short irregular diverticula, but the margins of 

 the canals are of a rather irregular wavy nature, so that the pinnate arrangement of 

 the gonads, conspicuous in P. lactea, is absent in this species. 



The tentacles are clo.sely packed together roun<l the margin of the umbrella, and 

 are like long, sleudcr threads, some of which measure 40-50 mm. in length. The 

 endoderm of the tentacle, iucludiug the basjil bulb, contains a dark reddish J)igment 

 (in formalin). Sections show that the pigment is in minute globules, either Isolated 

 or grouped in clusters. The ectoderm of the tentacle is thick, and composed of many 

 layers of very small cells, amongst wbith are uumerv)us long slender nematocysts, 

 about 15 /x in length. The nematocysts freq.uently congregate in clusters or layers 

 adjacent to the mesoglaea, and look in that position just like spicules. The basal bulbs 

 of the tentacles arc laterally compressed (IM. IL, fig. 8) and the upper (aboral) side of 

 the bulb is arcjied, but when viewed from tlic aboral side, the ba.sal bulbs look long 

 and tapering (PI. II., fig. 7). 



The cordyli are long and club-shaped (fig. i)), and are situatetl on the margin of 

 the umbrella close to the velum. There is usually only one cordylus between every 

 two tentacles. The cordyli are without pigment. Some of the cordyli possess just a 

 few nematocysts similar U) those in the tentjicles. 1 have not noticed nematocysts in 

 a cordylus before, but here at any rate is a"»i exception to the rule. Ilaeckel (1882) in 

 his description of Ptijchogena pinnulata states that the cordyli appear chalk-white in 



