Note on a species of LucernnHa from Japan. 



By 

 A. Oka, Ph. D. 



During a short stay at Kognshi, Nagato, last April, I was able to 

 collect among others a medusa evidently belonging to the peculiar genus 

 Lucernaria, of which only one representative* has, so far, been recorded 

 from our coasts. As this medusa presents many characteristics that seem 

 to differ more or less distinctly from those of all the other species of the 

 same genus, I think it will not be useless to give a short account of it. 



Description. As in all other Lucernaria:, the body of this medusa 

 consists of two portions, the calyx and the stalk (Fig. 1). 



The stalk has the shape of a short cylinder measuring 4 mm. in 

 length and '2 mm. in diameter. The lower end, corresponding to the 

 base of the cylinder, acts as sucker, by means of which the animal 

 attaches itself upon the substratum. 



The calyx, which is by far the more important division of the body, 

 is not cup-shaped, as we generally find it in the medusoe of the Family 

 Lucernariidce. On the contrary, it represents a slender Greek cross, 

 the arms of which are divided in two at the extremity (Fig. 2). Of this 

 cross we distinguish two sides, an oral and an aboral, corresponding 

 respectively to the inner and other surface of the cup. It is at the 

 centre of the aboral surface that the calyx is joined to the stalk. 



In the centre of the oral surface is found a very short tube, the 

 manubrium, at tne extremity of which the mouth opens. This tube, is 

 more or less quadrate in section. The lip of the mouth is dilated 

 somewhat in the form of a funnel, its outline being also quadrate. 



The arms of the cross are smooth on the aboral side, where we find 

 nothing but a slight undulation of the skin caused by the contraction of 



See this journal. Vol. V, Xo. 01. 



