450 THE VOYAGE OF II.M.S. CHALLENGER. 



The genus Holascus is especially represented in the south temperate zone, where three 

 species occurred, while the tropics only yielded one species, and the north temperate zone 

 none at all. Of the two known species of Malacosaccus one was found in the tropics, the 

 other in the south temperate zone. In the same way of the two Tsegerinae, the one, Tsegeria 

 pulchra, occurred in the south tropics, and the other, Walteria fiemmingii, in the south 

 temperate zone. 



In regard to Asconematidse, Aulascus jolmstoni was captured in the south temperate 

 zone* Sympagella mix in the north tropics, and Polyrhabdus oviformis and Balanites 

 pipetta in the south temperate zone. Of Caulophacinae, Caulojjhacus latus was found in 

 the south temperate zone, the other species, Caulophacus elegans, far removed in the 

 northern region, and finally Trachycaulus gurlitti in the south temperate zone. 



Of the genus Rossella, the only species obtained on the Challenger Expedition, Rossella 

 antarctica, was entirely confined to the south temperate zone, where it was found at four 

 different localities. In regard to the two species of Acanthascus and Batliydorus, two 

 at least belong to the fauna of the south temperate zone, while Bathydorus fimhriatus 

 occurred at two localities in the northern region. Ehahdocalyptus was represented by 

 one tropical species and by a second in the south temperate zone. It seems a note- 

 worthy fact that all known species of Crateromorpha were found in the tropics, while 

 Aidoclione was represented by one species in the tropics and by another in the south 

 temperate zone. Aidocalyx irregularis appears to be widely distributed, since it was 

 found both in the north and south temperate zones. The peculiar forms Caulocalyx 

 tener and Euryplegma aurictdare belong to the south temperate zone. 



Of the species of Hyalonema, which were somewhat uniformly distributed in all the 

 three zones, several were found in two zones, viz., Hyalonema (Stylocalyx) depressum 

 both in the tropics and in the north temperate zone, and Hyalonema (Stylocalyx) elegans 

 both in the tropics and in the south temperate zone. The species of Pheronema found by 

 the expedition belong to the tropics, the two species of Poliopogon to the temperate zones 

 {Poliopogon amadou in the north, Poliopogon gigas in the south), while Semj^erella 

 schultzei was tropical. 



Farrea occa occurred predominantly in the tropics, and Farrea clavigera exclusively 

 so, while undefined species of Farrea were found in all three zones. AU the five species 

 of Eurete obtained on the expedition were tropical, while the beautiful Lefroyella decora 

 occurred in the north temperate zone. 



Aphrocallistcs hocagei occurred both in the north temperate and in the tropical zone, 

 but Aphrocallistes ramosus was found in the latter alone. 



Chonelasma lamella and Chonelasma uncinatum occurred in the south temperate 

 zone, and undefined specimens of the same genus in each of the two other zones. 



The tropics yielded Hexactinella lata, Cyrtaidon, Fieldingia, and Sclerothalmnus, 

 while in the south temperate zone only an undefined specimen of Hexactinella was found. 



