On Specimens q/' Ceplialodiscus densus. 433 



CJfuus Leporillus. 

 Z. ffi/7i"ca/«s, Gould*. $. 63.10.22.15. S. Austn.lia 



{F. Stranye). Gould Coll. 



Geuus NoTOMYS. 

 N. cervitms, Gould. 53. 10. 22. 7. 29^ 6' S., 141° E. 



(Start). Gould Coll. 

 gouldi, Gould. 7. 1. 1. loO. W. Australia {J. 



Gilbert). Tomes Coll. 

 lonqicaudatm, Gould. 44. 7. 9. 15. Moore's R., W. A. 



(/. Gilbert). Gould Coll. 



Genus Conilurus. 

 C.constn(ctor,Og. $. 03.2.20.1. N.S.W. ((9. Ca- 



ley). Liunean Society. 



XLII. — On Specimens of Cephalodiscus densus dredged hy 

 the 'Challenger' in 1874 at Kerguelen Island. By W. G. 

 RiDEWOOD. 



[Plate XII.] 



The genus Cephalodiscus was founded upon material dredged 

 by the 'Challenger^ in January 1876 from Station 311 in 

 the Straits of Magellan ; the material was described in 1887 

 by M'Intosh and Harmer in the E.e|)orts of the 'Challenger' 

 Expedition (12), but preliminary accounts were published in 

 1882, 1883, and 1885 (10, 11, 8). For many years tliis 

 material of Cephalodiscus dodecalophiis remained the sole 

 representative of the genus, and it was not until 1903 that 

 Andersson (i) announced a rediscovery of Cephalodiscus by 

 the Swedish South-Polar Expedition, and Harmer (5) notitied 

 the securing of new species of the genus by the 'Siboga' 

 Expedition. Since that year numerous species have been 

 founded upon material obtained by the 'Siboga^ Expe- 

 dition (6), by Dr. Gilchrist (13), by the 'Discovery* Ex- 

 pedition (9, 14)^ by the Swedish South-Polar Expedition [2), 

 by Dr. Schei)otieff (19), by the Second French Antarctic 

 Expedition (3, 4), by the Scottish National Antarctic Expe- 

 dition (7), and by the British Antarctic ('Terra Nova') 

 Expedition (16). 



U[) to the present time sixteen species of Cephalodiscus 

 have been described, but some of the s|)ecific names may iiave 

 to be regarded as synonyms (see 16, p. 14, footnote). A 

 synopsis of all the species of Cephalodiscus at present known 



* Tlie Museuui received from Gould two specimens of this animal, 

 though he stated that he had only one. It seems, therefore, advisable to 

 nominate the specimen that best tits the description as the lectotype. 



Ann. d£ Mag. N. Hist. Ser. 9. Vol. viii. 28 



