CORONATE PKRICOLPA. 541 



Order CORONATJE Vanhoffen, 1892. 



Discometluij: (in part), HAUCKKI., 1866, Generclle Morphologic, Bd. 2, p. 60; 1880, Syst. der Meduscn, p. 450. 



Cron,a.r, VA \nutt IN. 1892, Ergeb. dcr Plankton Exped., Bd. 2, K. c., p. zi; 1901, \Vissen. Krgcb. dcutsch. Ticfsee Exped., 



Dampfcr I'aldivia, Bd. 3, Lief, l, p. 11; 1906, Nordisches Plankton, Acraspede Mcdusen, Nr. 11, p. 41. 

 Coronata, MAAS, 1903, Scyphomedusen dcr Siboga Expedition, Monog. 1 1, p. 5; 1907, Ergeb. FoitKhritte der Zool., Bd. I, pp. 191, 



199. BIGELOW, H. B., 1909, M< m. Mus. Comp. Zool. at Harvard College, vol. 37, p. 20. 



CHARACTFRS OF THE CORONATJE. 



Scyphomedusa; with marginal tentacles, a single central mouth-opening, and \vith the 

 hell-margin clett into lappets. The rhopaha arise from clefts between these lappets, and 

 their entodermal cores contain a terminal mass of crystalline concretions of entodermal origin. 

 Ocelli may or may not be present. The medusie are free-swimming and have no aboral 

 stalk for attachment. 



With a circular, or coronal, furrow in the exumbrella, and peripheral to this there is a zone 

 of gelatinous thickenings in the radii of the tentacles and sense-organs. These thickenings, 

 or pedaha, are divided one from another by radiating clefts which alternate in position with 

 the marginal sense-organs and the tentacles, and are in the middle (axial) lines of the marginal 

 lappets. These marginal lappets project beyond the zone of the pedaha. The tentacles are 

 solid, or not hollow, throughout their lengths. The throat-tube is simple, short, and provided 

 with simple lips, without curtain-like appendages. 



The families of the Coronats are as follows: 



Periph\U'nLc CLAUS, 1886. 4 intcrradial rhopalia anil 4 or more tentacles. 



Parapliylliniil.e MAAS, 1903. 4 perradial rhopalia and 4 or more tentacles. 



Ephyropsidts CLAUS, 1883. 8 rhopalia (4 perradial and 4 interradial) and 8 or more tentacles. 



Collaspitlx HAECKEL, 1880. Numerous rhopalia, alternating with an equal number of tentacles. 



AtoreUitia: VA\H<UI>X, 1902. With 6 rhopalia and 6 tentacles. 



Family PERIPHYLLID^E sensu Claus, 1886. 



PeromeJusa: (in part), HAECKEL, 1880, Syst. der Medusen, p. 396. 



Perifhyllijj, GLAUS, 1886, Class, der Me.lusen, Arbeit. Zo,.l. In t. Univ. VA'ien, Bd. 7, pp. 97-1 10. VANHIH TFN, 1892, Akalephen 



der Plankton Expedition, Bd. 2, K. d., p. 2 1 . MAAS, iS9^, Mem. Mus. Comp. Zool. at Harvard College, vol. 23, No. i, p. 28; 



1906, Fauna Arctic a, Bd. 4, Lfg. 3, p. eol . Y\\HI>H > \, i<|o6. \nr disc lies Plankton, No. 1 1, Acraspede Medusen, p. 41 . 



BII.M.OW, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 23. 

 PtromeJustt, VON LENDENFELD, 1884, Proc. Linncan Soc. New South VA'.ili-s, vol. 9, p. 166. 



FAMILY CHARACTERS. 



Coronatae with 4 interradial pedaha which bear marginal sense-clubs, and with 4, or 

 more, pedaha which bear tentacles. 



The genera of the Periphylliclae are as follows: 



Ptricolpa HAH KM, 1880, sensu Vanhoffen, 1902. With 4 prrradi.il tentacles, S adr.idul l.ippets, 8 gonads. 

 Periphylla STEF.NSTRUP, 1837. With (4 X 3) 12 tentacle-. 4 perra.ii.il, S adrajial. id lappets, 8 gonads. 

 Periphyllopsis VANHOFFEN, 1900. With (4 X 5) 20 tentacles, 24 l.ipi n . 

 (?) Nauphantofsil KIWKIS, 1885; sensu Vanhfiffen, n)O2. \\'ith (4 X 7) 28 tentacles, 32 lappets. 



Genus PERICOLPA Haeckel sensu Vanhoffen. 



Ptrifolpa+- Pericr\ptci, HAICKM, iSSo, S^t. der Medusen, pp. 413, 414, 640. 



Pericolpa, VANiiiJFFr-j, 1902, Wi <n. l.iri h. deutscli. Tiefs.-e I i .; ui, Bd. ^, Lfg. i , p. 50.- -MAAS, 1903, Scyphomedusen 



dcr Siboga Expcd., Monog. ll, p. 12; 1906, Die Arktischen Medusen, Fauna Arctica, Bd. 4, p. 501. 



GENERIC CHARACTERS. 



Periphyllidae with 4 interradial rhopalia. 4 perradial tentacles, 8 adradial lappets. The 

 8 gonads are adradial or on both sides of the 4 interradii. 



Haeckel's P?ricr\i>tu is doubtless only a more advanced stage in the growth of Pericolpa. 

 The interradial t;i-iiiol;c are solid in the young, but become hollowed In the development of 

 4 pits in the floor of the subumbrella, and the gastral filaments increase with age. In the 

 structure of the gastrovascular system this genus resembles Pcrif>li\lln, and were it not for 

 the probability that the number of metameres apparently does not increase in the free eph\ ra 



