Subordo I. 



PHYLLOCARIDA 



(Leptostraca, Claus). 



Character. — Braiichiopoder med den forreste 

 Del af Legemet dækket af et stort, mere eller min- 

 dre udpræget tveklappet Rygskjold, forsynet fortil 

 med en bevægelig Pandeplade. Den bagre Del af 

 KrojDpeu cylindrisk, afsmalnende bagtil og endende 

 med 2 bevægelige Grene (Furca), mel] em hvilke der 

 undertiden er en dolkformig Haleplade. Øinene stil- 

 kede og bevægelige. Begge Par Folere vel udviklede, 

 mangeleddede, 2det Par enkle, hverken locomotoriske 

 eller prehensile. Alle Forkropslemraer bag Mund- 

 delene udelukkende respiratoriske ; Bagkropslem- 

 merne meget ulig disse og fordetmeste locomotoriske, 

 manglende paa de bagerste Segmenter. Havdyr. 



Alm. Bemærkninger. — Typen for denne Under- 

 orden er den i mange Henseender hoist mærkvær- 

 dige og anomale Slægt NebnUa, om hvis systematiske 

 Stilling der har hersket den storste Uenighed blandt 

 Zoologerne. Medens man før ialmiudelighed med 

 Milne-Edwards henregnede denne Form til Pliyllo- 

 poderne, har i den nyere Tid, navnlig efter de af 

 Prof. Claus anstillede Undersøgelser, en ganske anden, 

 allerede meget tidligt af enkelte Naturforskere ytret 

 Opfatning vundet Overhaand, nemlig at denne Form 

 slutter sig nærmest til de stilkoiede Krebsdyr, navn- 

 lig til visse Schizopoder (Euphausiidæ), og at den 

 saaledes snarere tilhører Malacostraceernes Afdeling 

 end Entomostaceerne. Jeg har paa et andet Sted ') 

 nærmere udviklet mine Grunde til fremdeles at bi- 

 beholde denne Slægt under Entomostraceerne, og 

 blandt disse er Branchiopoderne de, hvormed nær- 



Sub-Order I. 



PHYLLOCARIDA 



(Leptostraca, Claus). 



') Report on the Phyllocarida, collected during the Expedition 

 of H. M. S. t Challenger». 



Characters. — Branchiopods, with the foremost 

 portion of the bod}' covered by a large, more or 

 less distinctly bi-lobate carapace, furnished anteri- 

 orly with a mobile frontal plate. The posterior por- 

 tion of the body cylindrical tapering backwards, and 

 terminating in 2 mobile rami (furca), between which 

 there is occasionally a mucroniform caudal plate 

 Eyes pediinculated and moliile. Both pairs of antennæ 

 well developed, multiarticulate ; 2nd pair simple, 

 neither locomotory nor prehensile. All the appen- 

 dages of the anterior division of the body behind 

 the oral parts, exclusively respirator}'. The appen- 

 dages of the posterior division of the body very 

 unlike the former and chiefl}' locomotor}^; absent 

 on the posterior segments. Marine animals. 



General remarks. The tj'pe of this sub-order 

 is — the in many respects highlj^ remarkable and 

 anomalous genus — Nebalia, regarding whose sys- 

 tematic position the greatest difference of opinion 

 has prevailed among zoologists. Whilst, previously', 

 zoologists in general agreed with Milne-Edwards 

 in assigning this form to the PlujUopods, there has 

 prevailed in later times, especially since the result 

 of the investigations made by Prof. Claus, a 

 quite different opinion, which alreadj' much earlier 

 was expressed by a few naturalists, viz: that this 

 form approximates closest to the stalk-ej'^ed Crusta- 

 ceans, especially to certain Schizopods (Euphausiidæ), 

 and that it, therefore, pertains rather to the Malaco- 

 stracan than to the Entomostracan division. I have 

 elsewhere ') explained, in greater detail, my reasons 

 for still retaining this genus under the Entomo- 



') Report on the Phyllocfirida collected during the Expedition 

 of H. M. S. 'Challenger». 



