Classification of the Arthropoda. 57 



informed as to my opinion wlien he prepared his Limulus- 

 article, he certainly ought since then, and before publicly 

 bringing such serious accusations against me, to have made 

 himself better acquainted with ray writings. 



2. In the excess of his zeal it has quite escaped Prof. Ray 

 Lankester that my conception is very different from his, and 

 has nothing at all to do with the assertions and conclusions 

 contained in the Zi'mw/MS-article, so far as these dixo. peculiar 

 to Mm. Not only do I treat the derivation of the Scorpions 

 fi'om the Gigantostraca merely as a probable one, but I also 

 in those words appeal, in the first place, only to the insuffi- 

 cient evidence of the Crustacean nature of the latter (Crusta- 

 cean in the sense of the Eucrustacea), in order, in the next 

 sentence, to seek the data for their relationship to the Arach- 

 noidea in developmental history. Consequently, even without 

 citing the Limulus-?iX\\c\Q, I exclude, as arguments, the sup- 

 posed data derived from the perfect organism. 



Or has Ray Lankester forgotten the criticism passed upon 

 the contents of his Limulus-SinicXo, by no other than Packard, 

 the author of an important work on the development of Limu- 

 lus? Has it passed from his memory that Packard has 

 demonstrated his parallelizations, almost point by point, to be 

 constructions of the imagination ? (see S. F. Packard, " Is 

 Limulus an Arachnid ? " ' American Naturalist,' 1882). But 

 even in this case he ought not to have overlooked the fact 

 that I do not refer to the agreements deduced from the form 

 and structure of the perfect organism, and from this he ought 

 to have concluded at least that 1 have no great confidence in 

 them. 



Let us now look a little more closely into the contents of 

 the celebrated Limulus- ii\\.\Q\& and the other writings of Ray 

 Lankester related to it, in order to judge of the value of the 

 evidence for regarding Limulus as an Arachnid which they 

 contain. 



In opposition to Ray Lankester's assertion that Limulus 

 and Scorj)io agree, segment for segment, Packard has shown 

 from the development that in Limulus there are not eighteen 

 but only fourteen segments present, and consequently that 

 four segments are added as " metaphysical inventions." 

 " Our author," adds Packard, " sets out with the foregone 

 conclusion that he ' must ' find in the abdominal carapace of 

 Limulus the representatives of the twelve abdominal segments 

 of the Scorpion ; and so, with a method of his own, he creates 

 them out of his inner consciousness." No better judgment is 

 passed upon the homologization of the six pairs of limbs of 

 the abdomen with the triangular sternite, the pectinate appen- 

 dages, and the four pairs of lung-sacs of the Scorpion. 



