■92 K. KISHIXOUYE. 



})terid((, Ptcnigolns, &t*.). Two pair^ <^f eye.s («hu', lateral and roni- 

 ])ouii(l, the other, median and simple), the ambulatory appendages 

 around the mouth, and the .sworddike tel^on, are the points of re- 

 semblance between them, ihit tliere are msmy differences ; the chief 

 ones among which are the want of the facial suture in the dorsal surface 

 of the céphalothorax, and the fact that the a])pendage8 are divided into 

 ni(jre than six segments in the ^lerostomata. The Merostomata re- 

 semble closely tlie Scorpi(jnida, an order of the Arachnida. Hence we 

 find a relation between Liiiiidns and the Arachnida. 



Fr()m early times the genetic relation between Limuhis and the 

 Arachnida has been maintained, and at present we do not doubt the 

 reality of such a relationship; but ^vhether Liiiudas ought to be 

 classified anion^' the Arachnida or amono- the Crustacea, or be made 

 into an independent class is still an o])en question. ]n order to show 

 at a glance in what points Liinuhis resembles, and in Avhat j'oints it 

 differs from, the Crustacea on the one hand and the Arachnida on the 

 other, I liave introduced the table on the next [>age. I venture to 

 think that there are some new j)oints which h;i\e not been noticed by 

 previous writers but which !ire nevertheless quite signilicant. 



From the table it will be seen that Liiinilus differs in many 

 points from both the Crustacea and the Aracluuda. With the sole 

 exception of the facial suture, there is no important point in which 

 Llimdas diiters from Ixjth the Crustacea and the Arachnida. In those 

 points in wliich Liiinilus differs froni the Arachnida, it resendjles the 

 Crustacea, and where it ditfers from the Crustacea it resembles the 

 Arachnida. Tlierefore it appears to me not ad\ isable to place Ijliiiidiis 

 in either class, or to make it an appendix to either. On the whole it 

 seems safe, or rather necessary, to make an independent class for Liiituhis 

 a] id the Trilobita. 



Hitherto the Merostomata have u'enerallv l»een consideied lo be 



