X GYMNOBLASTEA ANTHOMEDUSAE 273 



the family Tiaridae. Of these Tiara, a very brightly coloured 

 jelly-fish sometimes attaining a height of 40 mm., is found on 

 the British coasts, and Amphinema is found in considerable 

 numbers at Plymouth in September. Turritopsis is a Medusa 

 with a hydrosome stage like Bendroclava. For Stomatoca, see 

 p. 415. 



Fam. Corymorphidae.- — This family contains the interesting 

 British species Corymorpha nutans. The hydrosome stage con- 

 sists of a solitary zooid of great size, 50-75 mm. in length, 

 provided with two circlets of numerous long filiform tentacles. 

 The free-swimming Medusae are produced in great numbers on 

 the region between the two circlets of tentacles. These M«dusae 

 were formerly known by the name Steenstrupia, and are note- 

 worthy in having only one long moniliform tentacle, opposite to 

 one of the radial canals. 



The gigantic Monocaulus imperator of Allman was obtained by 

 the " Challenger " at the great depth of 2900 fathoms off the coast 

 of Japan. It was nearly eight feet in length. More recently 

 Miyajima^ has described a specimen from 250 fathoms in the 

 same seas which was 700 mm. (27'5 in.) in length. Miyajima's 

 specimen resembles those described by Mark from 300 fathoms 

 off the Pacific coast of North America as JBrancliiocerianthus 

 urceolus in the remarkable feature of a distinct bilateral arrange- 

 ment of the circlets of tentacles. Owing to the imperfect state 

 of preservation of the only specimen of Allman's species it is 

 difficult to determine whether it is also bilaterally symmetrical 

 and belongs to the same species as the specimens described by 

 Mark and Miyajima. These deep-sea giant species, however, appear 

 to differ from Corymorpha in having adelocodonic gonophores. 



Fam. Hydrolaridae. — This family contains the remarkable 

 genus Lar, which was discovered by Gosse attached to the margin 

 of the tubes of the marine Polychaete worm Sabella. The 

 zooids have only two tentacles, and exhibit during life curious 

 bowing and bending movements which have been compared with 

 the exercises of a gymnast. The Medusae (Fig. 132, A and B) 

 have been known for a long time by the name Willsia, but 

 their life-history has only recently been worked out by Browne.^ 



' Journ. Coll. Sci. Tokyo, xiii. 1900, p. 235 (with a beautiful coloured 

 illustration). 



2 Proc. Zool. Soc. 1897, p. 818. 

 VOL. I '^ 



