2 W. A. IIKRDMAN. 



chnrnctfi-isctl l>v tlio aliuii.laino uii.l the larjic size of the imliviiluals of a eompaiativcly 

 few sixries. Kvery «-(jIleetion that lias been brought home from the Antarctic since 

 has »leiiif>nstrate<l the correctness of this conclusion, and 1 fnul that Dr. Sluiter, in a 

 recent i»ultIication,* draws attention to the same set of facts. The a.spcct, for example, 

 of the present collection, with its compftratively few species, is in marked contrast to 

 that of a collection from the Indian Ocean, or any other tropical or sub-tropical region, 

 where the sj)ccics -tire numerous and small. In tlie present cdMci-tion as large 

 specimens we have Stt/ela xpi'dnhilis, measuring 18 cm., Muhinla lioihjsimi, measuring 

 4 i-ni., and llnlnci/iitliiii selnfiii up to 10 cm. ; while in the colle<tion of the .Scotti.sh 

 Antarctic Expeiliti(m, nt>w in my hands, this appearance o* a fauna characteri.sed by 

 few but giganti<; .species is still more marked. This po.sse.s.sion of unusually large 

 sjK-cies is a chanicter in which the far .southern .seas certainly seem to surpass 

 those of the far North. The Arctic Tunicate fauna, which is iiow .so very much 

 lietter known than tin- Antarctic, .shows no smli markcil asscm])lage of gigantic 

 forms. 



Although .so many expeditions have collected in Antarctic seas of late, it lannot 

 be said yet that the fauna is sutiiciently well known, as .several of the ccillections have 

 not yet been worked out. We have reports upon the ' Valdivia,' the ' Charcot,' and 

 the 'Southern Cross' Tunicata, but tho.se of the ' Bclgica,' the 'Scotia,' and the 

 'Gauss' are not yet publi.shed. There will undou])tedly be a certain amount of 

 overlapping in the collections from these various expeditious, but ea<li will probably 

 add .something to our knowledge of the Antarctic Tuuicata. That knowledge is not 

 yet sutiiciently detailed to }3ermit of a clo.se comijarison with the corrcsjjonding Arctic 

 fauna ; but a certain similarity in families and genera — which does not, however, 

 extend to identity of species — is noticeable. For example, amongst simple Ascidians, 

 both polar regions are characterised by the presence of Ascidiidae and Molgulidae, while 

 tropical .seas have more Cynthiidic. Other resemblances might be pointed out, but 

 I believe the time has not yet come to make a detailed analysis of the two polar 

 faunas. 



One dilHculty met with in attempting any record of a section of the Antarctic 

 fauna is the ab.scnce of any natural nortliern limit and the want of agreement as to 

 where such a limit .should be arbitrarily placed. 



If we take the Antarctic region in a wide sense as including the Strait of Magellan, 

 Tierra del Fucgo, the Falkland Islands and Kerguelen Island, then we have a large 

 recorded fauna belonging to all groups of the Tunicata and characteri.sed by abundance 

 of siR'cimens belonging to many species (see, for example, those collected during the 

 'Challenger' expedition). If, however, we use the term 'Antarctic' in a more 

 restricted .sen.se, as including oidy the sea-area .south of, say, (\(f S. latitude, then we 

 cut out all land except the shores of the Antarctic continent it.self ; but even from this 

 restricted region some fifty species of Tunicata arc already known. The following 



• KxiuVlilion ,\iitarcticiue fran^iiise (Cbaicol). Tuiiiiirrs. I'luis, p. 1. 



