354 M. Sars on the Nurse-Genus Corymorpha and its Species, 



new genus under the name oi Amalthaa uvifera, is also certainly 

 a species, and apparently a new one, of my genus Corymorpha. 

 Leuckart is therefore wrong when, in his " Jahresbericht " 

 (Archiv, 1854, ii. p. 443), he identifies this with the Myriothela 

 arctica described by me in 1850*, which differs from it not only 

 specifically, but even generically. 



Lastly, Alder, in his ' Catalogue of the Zoophytes of North- 

 umberland and Durham' (1857, p. 18), has shown that a Hy- 

 droid polype imperfectly described by Johnston, and referred by 

 him to the genus Hydractinia (Hist, of British Zoophytes, p. 463, 

 fig. 79 a), is a new species of Corymorpha — C.nana, Alder. 



Besides the earliest-known species, C. nutans, I have at dif- 

 ferent times found on the northern coasts three other new species, 

 by which the total number is raised to seven, of which six are 

 northern (three even arctic) and one tropical. 



As regards the determination of the species, these have so 

 much in common in the form of the body and tentacles, and the 

 number of the latter appears to be so little fixed, and also vari- 

 able according to age, that it becomes extremely difficult to 

 distinguish and characterize these forms satisfactorily. From 

 my experience, the best and most certain characters are furnished 

 by the Medusa-buds produced from them. From the form and 

 structure of these, and with the addition of some other characters 

 which are certainly less reliable, I have endeavoured to charac- 

 terize the species observed by me. 



1. Corymorpha nutans, Sars. 



Sars, Beskr. og Jagtt. over Dyr ved den Bergenske Kyst, 1835, p. 6, tab. 1. 

 fig. 3 a-f; Forbes and Goodsir, Ann. Nat. Hist. 1840, vol. v. p. 309; 

 Johnston, History of British Zoo])hytes, p. 54, tab. 7- figs. 3-6. 



Proles hydriformis 3-4-pollicaris, tentaculis inferioribus filifor- 

 mibus longissimis uniserialibus 40-50, superioribus brevissimis nu- 

 merosissimis sparsis ; pedunculis gemmigeris circiter 1 5-20, tenui- 

 bus, longiusculis, ramosis, ramulis alternantibus apice gemmis medu- 

 sinis numerosis minimis dense accumulatis obsitis. 



Proles medusiformis decidua, pallio campanulato apice conico, 

 canales quatuor radiantes exbibeute, antice aperto margine oblique 

 truncate ibique bulbis quatuor marginalibus sequidistantibus ornato, 

 quorum unus solummodo in cirrum cylindrioum porrectum evolvitur. 



I first discovered this species in the year 1830, near Glesvaer, 

 in the vicinity of Bergen, at a depth of 30-40 fathoms, on 

 muddy sand ; I afterwards met with it near Manger, at a depth 

 of 8-10 fathoms, on a sandy bottom; and lastly, in my first 

 northern journey, in the year 1849, a pair of specimens were 

 found, mixed with the following species, which occurred in great 



* Reise i Lofoten og Finmarken, p. 134. 



