48 EDWARD T. BROWNE. 



SEM^EOSTOMATA. 

 FAMILY CYANEID^E. 



DESMONEMA, L. Agassiz, 1862. 

 (sens. em. Maas, 1908.) 



Generic Character. Cyaneidse with eight rhopalia ; with eight straight or nearly 

 straight groups of tentacles, each group containing only a single row of tentacles ; 

 with eight tentacular and sixteen rhopaliar lobes ; without radial muscles on the lobes. 



In 1862 L. Agassiz placed Chrysaora gaudichaudi, Lesson (1830), in a new 

 genus called Desmonema, and at the same time he described Couthouyia pendula as a 

 new genus and species. Prof. Haeckel (1880) emended the definition of the genus 

 Desmonema and reduced Couthouyia to a synonym of it. Dr. Vanhoffen (1888) has 

 also emended the generic definition of Desmonema and added a new species called 

 Desmonema chierchiana[_um~], on the ground that the earlier species were not recog- 

 nisable owing to their imperfect descriptions. 



Until quite recently the above-mentioned species had only been recorded from the 

 Magellauic area, and it was generally considered tjmt they belonged to one genus, and 

 that probably only one species really existed. The occurrence of a second s'pecies of 

 Desmonema in the Magellanic area has still to be proved, as Desmonema chierchianum 

 is the only one which has been adequately described and figured from that area. 



Dr. Vanhoffen (1908) in his report on the 'Gauss' Medusae has recorded 

 Desmonema chierchianum from Kerguelen and Heard Islands, and also large tentacles of 

 a Desmonema, and early stages from the ' Gauss ' Winter Quarters of Kaiser Wilhelm II. 

 Land on the Antarctic continent. 



Dr. Maas (1908) in his report on the Medusse collected by the ' Fran9ais ' 

 Antarctic expedition records a Desmonema under the name of Coutlwuyia gaudichaudi, 

 from Booth-Wandel Island, off Dauco's Land on the West Antarctic continent. From 

 Maas' description and figures there can be no doubt that his Couthouyia and the 

 Desmonema in the ' Southern Cross ' collection belohg to the same species. It must be 

 clearly understood that there is no proof whatever, at present, that Desmonema 

 (Couthouyia) gaudichaudi of Maas is identical with Desmonema (Chrysaora] gaudichaudi 

 of Lesson. 



Dr. Maas (1906) has also given a brief description, without figures, of an early 

 stage of a Medusa which he considers to be probably a young Couthouyia. This 

 specimen was taken in October, 1898, by the ' Belgica,' in lat. 69 59' S., long. 82 

 39' W., at a station which is south-west of the ' Francais ' station off Danco's Land. 

 According to Maas the specimen measured 15 mm. in diameter. It has sixteen 

 marginal lobes which show the beginnings of branched canals, and eight tentacles and 

 eight sense organs alternating with one another. This young Couthouyia is probably 

 an early stage of Desmonema gaudichaudi, because Desmonema chierchianum of a similar 



