113 



ganske stopper op. ] >et sker kun, iiaar Dyret plud- 

 selig form-oliges, i hvilket Tilfækle alle Dele af 

 Legemet liiirtigt trækkes ind i Skallen, livorpaa 

 ileiine hermetisk lukker sig ng Dyret synker til- 

 liunds. Meget snart aabner imidlertid Valvlerne 

 sig igjen, den forreste Del af Hovedet tilligemed 

 Aarerne strækker sig fursigtigt frem fortil, og Halen 

 hagtil, hvorpaa igjen Branehialfødderne begynder 

 sine rhythmiske svingende Bevægelser. 



Dyret s^-nes hovedsageligt at nære sig af o])- 

 smuldrede Plantedele, encellede Alger, maaske ogsaa 

 Infusorier. Disse Dele bliver ved Branehialfoddernes 

 Bevægelser hvirvlet ind i Skallen og passerer der- 

 etter bagfra fortil mellem Fodderne iniod Munden. 

 Kindbakkerne sees at være i stadig Aktivitet med 

 at bearl.ieide den af Munden optagne Xæring, som 

 deretter ved Hjæl]) af de talrige fra (_)verlæben til 

 Spiseroret gaaende Musklers Virkning bliver svælgt 

 og indfort i Tarmens forreste Del. Her undergaar 

 Føden en forelobig (_)plosningsproces ved det intenst 

 gule Secret, der udsondres af Leveren. Fordoielsen 

 synes idethele at gaa meget hurtigt for sig, idet 

 Tarmens ('ontenta hurtigt forandrer sin Farve, etter- 

 som de passerer bagtil, fra lyst gult eller orange 

 til et meget morkt brunt eller næsten sort. Med 

 visse Mellemrum bliver Exerementerne ved Ende- 

 tarmens Contractioner udstodte, ofte'i temmelia,- lanee 

 sammenhængende Masser. I Lighed med hvad Til- 

 fældet er hos Branchipodiderne, observeres ofte i 

 Tarnu-ørets Vægge energiske ]ieristaltiske Bevæ- 

 gelser. 



Som ovenfor anfort, har alle hidtil observerede 

 Individer af denne Form vist sig, ifolge sit hele 

 Udseende, at være Hunner, og alle Exemplarer bli- 

 ver ogsaa uden Undtagelse, naar de har opnaaet en 

 vis Grad af Udvikling, forsynede med de eharacteri- 

 stiske Ægpaketter under Skallens dorsale Del. Da 

 jeg liar observeret denne Form gjennem en Række 

 af Aar til forskjellige Tider af Sommeren, og tillige 

 gjentagne Gange har opdrættet den i mine Aqvarier 

 og kavt den gaaende her maanedsvis, tror jeg med 

 fuld Sikkerhed at kunne constatere, at Hanner over- 

 hovedet ikke existerer, og at altsaa nærvæ.rende 

 Phyllopodes For])lantning er exclusiv parthenogene- 

 tisk. Dette er saameget mere mærkeligt som For- 

 holdet er et helt andet med Arterne af den )neget 

 nærstaaende Slægt Eiilhnadia, hvor Forjdantningen 

 er udpræget bisexuel eller gamogenetisk, idet Han- 

 ner og Hunner til alle Tider synes at forekomme i 

 omtrent lige Antal. En Tid har jeg rigtignok staaet 

 i den Formening, at alle Individer af den her nm- 

 Imndlede Phyllopode maaske kunde være liermaphro- 

 ditiske eller rettere protandriske, idet visse Forliold 

 ved KjøDsorganernes Bygning s\-ntes mig at pege 

 i denne Retning; men Eesultateriie af de af mig 



15 — G. 0. Sårs: Fauna Korveoi^'- 



gracious, undulatory motion. It is, on the wh(de, 

 very seldom that this swinging motion of the 

 branchial legs entirely ceases; for it ha]ipens onlv 

 when the nnimal is suddenly alarmed, in which case 

 all the parts of the body are withdrawn into the 

 shell, wkicli then closes hermetically, and the animal 

 sinks to the bottom. The valves, however, very soon 

 reopen, and tlie fVn-e part of the head, together with 

 the oars, is cautiously extended in front, and the 

 tail behind, whereupon the bramdiial legs recom- 

 mence their rhythmical .swinging movements. 



The animal appears to feed principally on 

 broken pmfions of plants, unicellular algæ, aiul 

 possibly infiisoria. These are whirled into the shell 

 by the movements of tbe In-amdiial legs, and then 

 pass from b;ick to front between the legs towards 

 the mouth. The nmndil)les are seen to be con- 

 .stantly (iccu^ned in maniiiulating the food taken in 

 by the nniuth, which then, Ijy tlie aid of the inv 

 meroiis muscles running from the labrum to the 

 æsophagus, is swallowed and introduced into the 

 anterior part of the intestine. Here the food under- 

 goes a preliminary process of dissolution liy the 

 intensely yellow secretion deposited by the liver. 

 Dige.stion seems on the whole to take place ver\' 

 rapidly, the contents of the intestine quicklv 

 changing colour as they pass backwards, from light 

 yellow or orange to a very dark brown or almost 

 blai'k. At certain intervals the excrements are 

 ejected by the contractions of the rectum, often in 

 rather long, connected masses. As in the Branchi- 

 podidæ, energetic peristaltic movements maj' often 

 be observed in the walls of the intestinal tube. 



As stated above, all the specimens of this form 

 hitherto observed, have proved, from their whole 

 appearance, to be females; and all specimens, 

 witliout exception, when thej' have attained to a 

 certain degree of development, are provided witli 

 the characteristic cluster of eggs beneath the 

 dorsal part of the shell. Having observed this form 

 at diiferent jieriods of the summer through a series 

 of years, and having also reared it repeatedly in 

 my aijuaria, ■\^•here it has existed for months toge- 

 ther, I think I nuiy declare with perfect certainty 

 that males in reality do not exist, and that the 

 propagation of this Phyllopod is thus exclusively 

 ])arthenogenetic. This is so much the nujre remark- 

 able, as the circumstance is altogether different in 

 the species of the veiy nearly-allied genus Eiili- 

 iiiadia, where pro])agation is very nuirkedly bi-sexual 

 or gamogenetic, males and females seeming at all 

 seasons to occur in about e(|ual numbers. At one 

 tinn:" indeed, I was under the imjiression that all 

 the specimens of the Phj-llojiod in question might 

 perhaps be hermaphroditic, or rather ]>rotandric, as 

 certain circumstances in the structure of the sexual 

 organs seemed to me to point in that direction; 



