Till-: SK. Ml- KANT IM-Sll/l'S OF A DKCADK'S 



s^^I)^ ok tiik tcnk ata 



WILLIAM K. i;LLii;i! 



Morphology; 4, Knil.ry.iK.uy ; IMiysido-y. 



1. Taxonomy and Affinities. -'I'lirrc an- x-vcral (jucsiions of 

 general interest thai iiatui'ally arix' iiiidfi' thi- head. Tlie Tuni- 

 cata behig a coni])arativcly >iiiall (■la>s of animals, does the prog- 

 ress made in gettin-' lioM of lie iirw kiii<l> iinHcaif that we are 

 approaching conij)l('iciics> in this (hrcction":' 'l\\r class hcing as 

 thoroughly pelagic at mic extreme of it> liahilat, a^ tlioroiighly 

 littoral at another, ami as thoroughly ahys-al ai ^lill another as 



of number of kinds upon environment ^ 1- ilie pi-oMre-> ot knowl- 

 edge bringing out auythinu- concln-^ive as to the ureaier >ucces-. of 



Herdman's "Revised ( "lassilicalion of the 'I'nnicala,"' pul.li.hed 

 in 1891, contains a total of .".iN >pecie.. Thi^ list supposedly 

 includes all the species known at that time. By a reasonably 

 careful enumeration, those (lescril)ed since that year nutnher 521, 

 making a total of UH»!) s|)ecies now known. Tlu- better explored 

 portions of the sea, such as the Atlantic about the Hritish Islands, 

 the coasts of Continnual l-nn.pe. and the Me.lite.auPean. hase 

 yielded verv feu of the neu nuv.. prol.al.b not m-.re than half a 



water, lilerdman and .-luitcr : the M-a> traversed l.v the Sibou'a 

 h\pedition Hnit.-r ; the Cex l,>n region llerdn,an . th. southern 

 -ouih \me,i.an rei^ioi, Mi.hebui : the .fapan. ...a^l. , Oka 

 an.l llaitm.-vei : the I'a, ilic North Vnieii, an u-iou Ultter); 



