BY R. VON LENDENFELD, PH.D. 595 



191. PENNARIA ADAMSIA. nov. sp. 

 Plate XXV., fig. 45-48, Plate XXVI., fig. 49. 



The Medusostyles different in the two sexes, highly developed in 

 the male and more rudimentary in the female. 



The male Medusostyles" are slender, nearly cylindrical and 

 truncate at both ends. The four tentacles are about as long as 

 the Medusostyle is broad and move about freely. Ocelli are present, 

 although rudimentary as in P. cavolini (1.) The Spermatozoa fill 

 the space between the small Manubrium and the Subumbrella. In 

 the Aquarium, the Spermatozoa were ejected within an hour 

 after the Medusostyle had dropped off. Also, in this case active 

 contractions of the Umbrella could be observed in connection with 

 the ejection of the Sperma. 



The female Medusostyles are short and broad nearly spherical. 

 The tentacle rudiments are small, shorter than broad. No traces 

 of Ocelli are visible In the Aquarium these did not eject the ova 

 by contraction of the Umbrella. 



The Hydranths are slender, the proximal ones only about half 

 as large as the distal primary one of each pinna. They possess 8 

 slender capitate tentacles, placed in two verticils of four. Four 

 small ones on the top of the proboscis near the mouth, disposed 

 regularly in the four perradii and four longer ones on the body in 

 the four interradii, and 24 (always ?) filiform arms in the aboral 

 verticil. 



The stems bear from 15 to 20 pinnae, and there are about 8 

 Hydranths on each pinna. 



Colour : Perisarc of the Hydrorhiza and stem black and intrans 

 parent. Pinna transparent and yellow. Zooids white. 



Size : Length of stems 6-8 cm. Pinna 12 mm. Medusostyles 

 g 1*5 mm. long, - 7 mm. thick. £ I '6 mra - long, and as broad. 

 Hydranths 1*7 mm. long. 



Ontogenesis unknown. 



(1) A. v. Kolliker, Gegenbaur und Midler. Berichte iiber einige im 

 Herbste, 1852, in Messina angestellte vergleichend anatomische Unter- 

 suchungen. Zeitschrift fiir wiss. Zool. Band IV. Seite 303. 



