212 



the Teiimopk'iiriiup). cannot \w laken as deliniU'ly eslahlislu'd, until all 

 the chaiac lors available, inclu(linf» the slrucliire ol Ihc larva;, 

 have boon stndiod and duly lakon into considora lion. The struc- 

 Uiio ol Iho podicollaiia', of course, does not in itself give definite proof of 

 their aflinilios; also these characters may, doubtless, have dovoloped separ- 

 ately along (lin'eronl linos, as is seen from the case of Stronfiijlocenlmliis. not 

 to mention (iliiploriilmis vicnul(tris^). riierefore I would not consider e. g. 

 Iho position of the genus Lar<T/j///(/.s- in the family lu-hinida- as definitely 

 established, until it has boon proved that its larva also belongs to the 

 lu'hinoid type. Still less can the position of forms like Nolerhiniis magel- 

 hiniciis and Pseudechiiiiis (ilbocinclus, whore the characters of the pedicel- 

 laria* are very indistinct, bo regarded as settled, as long as we do not know 

 anything about their larvae. Upon the whole, the natural classification can- 

 not bo found through arranging the forms diagrammatically after this or 

 that characlei'; the interrelations and affinities being the result of organic 

 evolution and descent it is not likely that we will find liio true expression 

 thereof by means of a diagram. 



As a definite result it may bo staled that there is a dcfinile larval 

 t y p e c h a r a c 1 r i s t i c o f e a c h of the t h r e e f a m i 1 i e s , t h e E c h i n i d ae , 

 t he Toxopneuslida' and the Ec li i nomo Iridic. They may be shortly 

 characterized thus: 



The larvae of the Ecliinida' have in their first stage an elongated 

 body, supported by a long, more or less club-shaped body rod, the skeleton 

 forming no basket-structure. In Iho second stage there is no posterior 

 transverse rod, no posterolateral or vibratile lobes; epaulets are developed 

 at the base of the four main arms, often also one pair at the posterior end 

 of the body. Fenestrated rods are not known to occur within this tyjjo. 



The larva^ of the Toxopneustidai have in their first stage a short 

 body, the body rod being short and, together with the recurrent rod, 

 forming a basket-structure (excepting the genus Lytechiniis). In the second 

 stage there is a posterior transverse rod: posterolateral and vibratile lobes 

 are found, and there are often (always?) epaulets at the base of the four 

 main arms. The rods of the main arms sim])lo or fenestrated. 



The larvae of the Echinomolrida' have in the first stage a short, 

 obliquely truncated body, supported by a complicate basket-structure, the 

 recurrent rod being double. In the second stage there is a |)osterior trans- 

 verse rod; posterolateral and vibratile lobes are found, but no epaulets. 

 The rods of the main arms are fenestrated. 



') Coinp. tilt' author's "l^chinoloKical N()t(•^. " II. A new |)rimi|)Ii' of (^lassificatiuii. N'id. 

 Medtl. Nalurh. Koreii. Kolu'iiliavn. H>10. p. HI iioU'. 



