N 



POLYORCHIS. 



119 



POLYORCHIS A. AGASS. 



Polyorchis A. AGASS.; in Agassiz's Cont. Nat. Hist. U. S., IV. p. 349. 1862. 

 Mdicertwn Escu. (p.]).). Syst. der Acal., p. 105. 1829. 



Polyorchis penicillata A. AGASS. 



Polyorchis penicillata A. AGASS. ; in Agassiz's Cont. Nat. Hist. U. S., IV. p. 349. 1862. 

 Melicertum penicillatum ESCH. Syst. der Acal., p. 106, PL 8, Fig. 4. 1829. 

 At/laura penicillata EL. Man. d'Actinol., PI. 33, Fig. 4. 

 Melicertum penicillata LESS. Zooph. Acal., p. 293. 1843. 



This strange Jelly-fish I first found in 

 great numbers, while becalmed at the 

 entrance of the Straits of San Juan de 

 Fuca, in October, in company with large 

 numbers of a Medusa which I suppose to 

 be the Mesonema (Zyyodactyla) ccerules- 

 cens found b}^ Brandt in the latitude of 

 San Francisco, and which I had after- 

 wards occasion to observe again near 

 Punta de los Reyes, about twenty miles 

 northwest of San Francisco. It is also 

 quite common in the harbor of San Fran- 

 cisco during the winter months. It com- 

 bines the characters of several families, 

 has the long, pendent digestive cavity 

 of the Thaumantiadae (Fig. 179) ; the 

 ovaries hang independently, 

 four in number to each chy- 

 miferous tube (Fig. 180), 

 near the base of the diges- 

 tive cavity, as in the Tra- 

 chynemidos. But what is 

 very peculiar is the struc- 

 ture of the chymiferous 

 tubes ; instead of being sim- 

 ple or forking tubes, as we generally 

 find in the Hydroids, they remind us of 

 the structure of the chymiferous tubes in 

 Idyia, sending off short shoots into the 

 gelatinous disk at right angles, alternat- 



Fig. 1 79. A profile view, somewhat magnified, of 

 Polyorchis penicillata. 



Fig. 180. Ovaries of one of the chymiferous tubes. 



Fig. 179. 



Fig. 180. 



