708 Proceedings of the Royal Lish Academy. 



I cannot account for the extreme scarceness of this Medusa 

 at Valencia, and speculation is somewhat useless until its life- 

 histoiy is known. Its distrihution extends from the Shetlands 

 to Cornwall ; it was very abundant off the Eddystone in Sep- 

 tember, 1897, and May, 1898. 



This species may be distinguished from 2IargeUium octopuno- 

 tatum by the constant presence of four simple unbranched 

 oral tentacles, each terminating in a single cluster of nema- 

 tocysts. In Margellium the oral tentacles hare at least two 

 terminal and two lateral clusters of nematocysts. 

 Margelis autumnalis (Hartlaub). 



Botigainvillia autumnalis, Hartlaub, 1897, p. 465. Taf. xv. 



In 1896, six specimens were taken early in August. It was 

 the only species of Margelis seen dui'ing my visit in the 

 summer. 



In the tow-nettings sent to me by the Misses Delap eight 

 specimens were found early in November. 

 Margelis bella (Hartlaub), 



BougainviUia lella, Hartlaub, 1897, p. 470, Taf. xv.-xvi. 



A solitary specimen taken in May, 1895, and two during^ 

 August, 1897. 

 Margelis principis, Steenstrup. 



Margelis principis, Haeckel, 1879, p. 88, Taf. vi. 



Margelis Iritaimica, Browne, 1896, Irish Ifaturalist, p. 180. 



In 1895, this Medusa was not uncommon during Apiil and 

 May. 



In 1897, only a few specimens taken during April and May- 



The smallest specimen measured 1^ mm. in length. Oral 

 tentacles twice branched. Pour tentacles in each of the marginal 

 groups. 



The largest specimen measured 7 mm. in length and 8|- mm. 

 in width. Oral tentacles five times dichotomously branched, 

 24-26 tentacles in each of the four marginal gi'oups. 



In large specimens the umbrella is globular, and about as 

 long as wide. The stomach is on a broad but short peduncle ; 

 it has four large perradial lobes, which in some specimens reach 

 over the top of the umbrella-cavity. Upon the sides of these 

 lobes the gonads develop, and, when viewed from the top of 

 the umbrella, they represent a short, thick, perradial cross. 



