556 



MEDUS-li; OF THE WORLD. 



is at the extremity of a short, blunt-conical h\postoine, which is surrounded by an annulus 

 of about 40 solid filiform tentacles. 4 longitudinal partitions lined by entoderm extend 

 throughout the cavit\' of the stem. These do not meet in the center, but form only partial 

 septa, comparable with the mesenterial partitions of other sc)phostom;e ot Sc\plioniedus;c. 

 There is no marginal ring-canal. There are external, longitudinal and internal (meso- 

 dermail circular muscles. The polypites are translucent-white. 



Lobianco and Paul Mayer, 1890, found that eplura; o( Nausttho'e arise by strobilization 

 from this larva. The young eph\ra has only 4 gastric filaments and no tentacles. Kowal- 

 evski. i8"3, also observed the giving off of the eph\rae, but did not determine that thev were 

 Nausltho'e. 



It is not surprising that this peculiar larva should have received various names: Allman 

 calls it Stf plumose y pints ininibilis; F. E. Schulze describes it in detail under the name Spoiig- 

 icola fistularis; but its true nature was discovered by Lobianco and Paul Mayer, 1890. 



Haeckel's Natisican phtracum from Corfu, Mediterranean, may be identical with A'^. 

 punctata, but the 8 gonads tend to be grouped in 4 interradial pairs, forming a broken crescent 

 in each interradius, with a wide separation between the outwardly directed horns of each 



crescent. It ma\' have been described 

 from an abnormal or young specimen 

 oi N . puiutata (S>te Haeckel, 1880, Sit- 

 zungsber. Jena. Gesell. fiir Med. und 

 Natur., Jahrg. 1880, Feb. 20.) 



Nausithoe clausi Vanhoffen. 



Nausiihoi clausi, Vanhoffen, 1892, Ergeb. der Plank- 

 ton Expedition, Bd. 2, K. d., p. 14, taf. 4, fign. 

 1, 2. 



Disk about 9 mm. wide; central 

 lens-shaped dome of exumbrella flat, 

 smooth, unpitted, and without radial fur- 

 rows; 5 mm. wide, 16 well-developed 

 marginal pedalia. Medusa 3 times as 

 wide as high. 16 very blunt, 3-cornered 

 marginal lappets, three times as wide as 

 long and hardly one-ninth as long as 

 bell-radius. 8 adradial tentacles with 

 well-developed, conical bases. Tentacles 



Fig. 255. — Nausithoe rubra, after VanhoSen, ia f^aldifla Expedition, , i n i- o • i 



as loner as liell-radius. a mar<rinal sense- 

 organs alternating with tentacles. 8 gonads in the tentacular radii, very small, spherical, 

 only 1.3 as wide as the pedalia. Ring-muscle of subumbrella one-third as wide as bell- 

 radius. Numerous, small, simple gastric cirri arising in a linear row in each interradius. 

 Color (.?) 



Pacific Ocean east of the Caroline Islands. A single specimen appears to be A^. punctata 

 with poorly developed marginal-lappets and small gonads. 



Nausithoe challengeri VanhoSen. 



Nauphania challengeri, Haeckel, 1880, Syst. dcr Mcduscn, p. 487; 1881, Report Deep-sea Medusx, Challenger Eiped., Zool., 



vol. 4, p. 103, plates 27, 28, 20 figs. 

 Xausithoe challengeri, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Eiped. Valdiria, Bd. 3, Lfg. i, pp. 28, 31. 



Bell 12 mm. wide. Central lens of exumbrella separated by a deep annular furrow from 

 zone of pedalia. Somewhat less in diameter than bell-radius, its margin cleft by 16 radiating 

 furrows which do not extend to center of exumbrella. Marginal zone of pedalia well developed, 

 the 8 ocular being narrower than the 8 tentacular. Tapering tentacles somewhat longer than 

 bell-radius. The 8 large gonads are twice as long as w-ide and are elongated outwardly. 

 They are somewhat wider than the intervals between thern. 4 interradial clusters of simple 

 gastric cirri which arise at equal spaces in a single row irf each cluster and are not grouped 

 into brushes as in N. albatrossi. Each cluster has about 24 cirri. 



