244 Mil EDWARD T. BROWNE ON 



Desmonema chierchiana, Vanhoffen, 1888. (Plate II. fig. 2.) 



Desmonema chierchiana, Vanhoffen, 1888, p. 17, Taf. i. fig. 4. 

 ? Chrysaora gaudichaudi, Lesson, 1830, p. 114, pi. xiii. fig. 1. 

 ? Desmonema gaudichaudi, L. Agassiz, 1862, vol. iv. p. 166. 

 1 Desmonema gaudichaudi, Haeckel, 1880, p. 527. 

 1 Coutliomjia pendula, L. Agassiz, 1862, vol. iv. p. 118, p. 163. 

 % Desmonema pendula, Haeckel, 1880, p. 528. 



Station. — Stanley Harbour, Falkland Islands, 7th January 1903. 



The Scotia brought home three specimens, the largest of which is in splendid 

 condition, but the other two are not quite perfect. The large collection of medusas 

 made by Mr Rupert Vallentin in Stanley Harbour during the summer of 1898-1899 

 is still in my possession, and it contains two early stages of this species in excellent 

 condition. At the time when I examined Mr Vallentin's collection I was unable to 

 identify these young stages, as they were just too young to show clearly the generic 

 characters. By the aid of the Scotia specimens I have now been able to identify them, 

 and the five specimens form a nice series showing different stages in development. 



Specimen A (Vallentin Coll.). — This specimen is the youngest of the series, and 

 its development has not proceeded very far beyond the Ephyra stage. 



The umbrella is very thin and flat, measuring about 14 mm. in diameter. The ex- 

 umbrella has scattered over its surface numerous small clusters of nematocysts, which 

 are most prominent and conspicuous on the marginal lobes. The stomach is circular, 

 about 9 mm. in diameter, and has sixteen radiating pouches which are separated from 

 each other by radial septa. Eight of the pouches are opposite sense-organs, and eight 

 opposite the groups of tentacles. Within the stomach are four interradial bundles of 

 gastric filaments. From the mouth hang down four oral arms, which are a little 

 longer than the radius of the umbrella. They have the appearance of four large lips 

 folded along the centre. Their external surface is closely covered with small warts 

 containing nematocysts. 



There are eight adradial groups of tentacles, each group containing one long 

 tentacle and four to six minute tentacles or tentacular buds. The presence of one long 

 tentacle in each group indicates that in an earlier stage only eight tentacles are present. 

 The tentacles are within the margin of the umbrella, adjacent to the distal edge of the 

 gastral pouches. There are eight tentaculocysts (rhopalia), four perradial and four 

 interradial. 



The margin of the umbrella is divided into sixteen lobes or lappets by eight deep 

 clefts leading to the sense-organs, and by eight clefts, not quite so deep, which occur in 

 the middle of the tentacular lobes (the lobes opposite the groups of tentacles). At this 

 stage, however, each marginal lobe is composed of one ocular and half a tentacular lobe. 

 Later on this cleft in the middle of the tentacular lobes becomes obliterated. The 

 marginal lobes have a definite series of canals connected with the pouches of the 

 stomach. The canal system will be described in the next stage. 



