Notes ou some Hydromedusae from the Bay of Naples. 5S3 



as to the presence of the so-ealled spirai zooids among this species, 

 it not sustained. Both Weismann and Grobben bave shown their 

 preseuee, and I bave found them in every eolony examined. 



It had occurred to me diiriug the progress of my observatious 

 that possibly the tetrauematous condition of the medusae of the 

 Naples species might be due to some ineidental, or locai cause. I 

 therefore examined specimens from various localities, both male and 

 female, but found in every case that the medusae showed the sanie 

 absolute constancy in this feature. An examination of more than 

 one thousand specimens failed to detect any Variation in this re- 

 spect. 



I feel therefore confìdent that we bave bere a distinct species, 

 and acting- on the Suggestion of Haeckel, previously quoted, I pro- 

 pose for it the name Podocoryne conchicola, restoring the specitic 

 designation of Philippii, v7ho in 1842 described a hydroid under 

 the name Dysmorphosa conchicola^ wbich has since been considered 

 by many to bave been identical with Podocoryne carnea Sars. All- 

 MAN has, however, doubted the reliability of Philippi's descriptiou, 

 and furthermore the widespread use of Sars' name throughout the 

 literature should give pause to any attempt to readjust the matter 

 at present. 



The follo wing diagnostic characters are disti ncti ve of the me- 

 dusa, no occasìon arising in my judgment for a redescription of the 

 tropbosome, wbich differs in no significant way from that of typical 

 P. carnea Sars (a slightly larger size perhaps, being the only point 

 of differenee observed, and that not Constant): — 



Medusa (PI. 22 Fig. 26) : bell nearly hemispherical, slightly higher 

 than broad, size, Ü.8 ram high by O.Tbroad; velum rather wide; 

 mauubrium quadrate in shape, with four orai arms wbich are tipped 

 with Clusters of nematocysts ; marginai tentacles 4, perradially disposed, 

 and not becoming more numerous with age; when swimming 

 the tentacles usually coiled dosely against the beli as shown in 

 Fig. 26, when resting on the bottom of the aquarium or floating 

 sluggishly, tentacles usually extended at right angles to main axis 

 of body ; basai bulbs of tentacles rather prominent, and with brownish 

 pigment, though no detinite ocelli; outer surface of beli sparingly 

 dotted with nematocysts; gonads borne in four series on the base 

 of the manubrium. Bell very transparent and colorless, except at 



1 Arch. Naturg. 8. Jahrg. 1S42 pag. 37. 



