176 PERCY SLADEN TRUST EXPEDITION 



3. Zanclea orientalis nova species. (PI. 39, figs. 2 and 3.) 



Locality. North of Chagos, Lat. 4° 16' S., Long. 71° 53' E. 500 fms. (Wolfenden's 

 closing net). 18 May, 1905, G. 1 specimen. 



Description of the Species : — Umbrella a little higher than broad, with a rounded 

 summit and rather thin walls. Velum very narrow. Stomach cylindrical, about half 

 the length of the cavity of the umbrella. Mouth circular. Gonads extending nearly the 

 whole length of the stomach and forming interradial swellings. Two large opposite 

 perradial tentacles armed with globular batteries of nematocysts upon contractile stalks. 

 No tentacles in the other two opposite perradii, but only two very rudimentary internal 

 bulbs. Four perradial patches of nematocysts upon the margin of the umbrella, without 

 any groove or streak leading to them. 



Size. Umbrella about I'S mm. in width and 2 mm. in height. 



The character selected to distinguish this new species is the presence of rather broad 

 perradial patches of nematocysts upon the margin of the umbrella. These patches (fig. 3) 

 are situated directly on the margin and have no tracks or grooves leading to them. 

 There are no longitudinal bands of nematocysts upon the ex-umbrella, but its whole 

 surface is sprinkled with small isolated nematocysts. The tentacles are in a contracted 

 condition and so also are the stalked batteries of nematocysts. The exterior of the 

 battery is covered with a thin layer of ectoderm, and the nematocysts are packed 

 away inside, practically filling the whole of the interior of the ball. The stalked 

 batteries of nematocysts are along only the outer side of the tentacles. 



The depth at which this specimen was taken is not trustworthy, as the messengers 

 working the net were not acting properly. 



4. Zanclea juv. 



Locality. Alphonse Is., Surface. 7 Oct. 1905, ee. 1 specimen. 



The umbrella is nearly 2'5 mm. in height and 1*75 mm. in width, with thick walls 

 and a rounded summit. The stomach is short, about O'o mm. in length, and with 

 a circular mouth. Four perradial canals. There are two opposite perradial tentacles 

 armed along their outer side with stalked batteries of nematocysts, which are oval in 

 shape, about twice as long as wide, and about twice the size of those in the batteries of 

 Zanclea orientalis. The stalks have the appearance of rather fine filaments, studded with 

 small isolated nematocysts. In the other two opposite perradii there is the merest trace 

 of a marginal bulb, which has not the appearance of ever developing a tentacle. Upon 

 the ex-umbrella there are four perradial tracks of nematocysts. They are very short, just 

 curling over the margin and terminating with a small cluster of nematocysts. 



This is evidently a young medusa, as there are no signs of gonads upon the 

 stomach. 



5. Zanclea %. 



Locality. Chagos, Peros Atoll. 75 — fms. 30 June, 1905, M. 1 specimen. 

 The umbrella is thick but contracted and torn ; about 2 '5 mm. in width and 2 mm. 

 in height. The stomach is badly damaged, but there are cells at its base, interradially 



