160 PANTOPODA. 



formerly regarded. Dohrn considers it to be, like the Nauplius, 

 a modified Annelid larva, and derives the Pantopoda from forms 

 resembling the Annelida. Morgan, however, is unable to accept this 

 conclusion, but regards it as a secondary larval form which can no 

 longer be referred to the Annelidan larva. It seems to us that this 

 last view might easily be reconciled with that of Dohrn. 



Dohrn derives the Pantopoda from the Annelida, without relating 

 them to the Crustacea and the Arachnida. He thus regards them 

 as a distinct, independent group, and this is also Hoek's view 

 (No. 7). Morgan, on the contrary, favours the relationship to 

 the Arachnida, a view towards which Schimkewitsch also inclines 

 (No. 15). He attributes the Pantopoda to the same racial form 

 as the Arachnida, but believes that they branched off early and 

 developed in a different direction. The most recent investigator of 

 the Pantopoda, G. 0. Sars (No. 13), does not connect them with 

 either the Crustacea or the Arachnida, but wishes to make them 

 into a separate class. In consequence of all these varying opinions 

 we are unable to define with any degree of certainty the systematic 

 position of the Pantopoda. On the whole, according to the present 

 state of our knowledge, we shall do best to follow the conclusions 

 of Dohrn (No. 4). If, notwithstanding this last decision, we 

 have appeared to place the Pantopoda as next in order to the 

 Arachnida, and to dwell on the possibility of the relationship of 

 these two forms, this was done for practical purposes, since we 

 should otherwise have been obliged to classify them in a less satis- 

 factory manner, because they seem to show some slight similarity 

 in their development, and a convergence in some anatomical points, 



to the Arachnida.* 



LITERATURE. 



Only a few of the many treatises describing the ontogenetic stages 

 of the Pantopoda are here enumerated. The following literature, 

 however, will afford further references. 



1. Adlerz, G. Bidrag till Pantopodernas Morfologi och Utveck- 



lings historia. Bihang till Tc. Svenska Vetenskap. Akad. 

 Handlinrjar. Ed. xiii. Afd. iv. No. 11. Stockholm, 1888. 



2. Claus, C. Ueber den feineren Bau des Medianauges der 



Crustaceen. Anz. k. k. Akad. Wiss. Wien, Mai, 1891. 



No. 12. 



* [Ihle (App. to Lit. on Pantopoda, No. I.) holds that it is impossible to ally 

 the Pantopoda with the Arachnida or with the Crustacea, but thinks that the 

 Myriopoda may be regarded as the ancestral stock. He lays special stress on 

 the presence of a pair of abdominal appendages. — Ed.] 



