lit; University of California Publications in Zoology. IVol.6 



and all other adult Cerianthids, so i'jir as known, in possessing 

 structures which resemble in Jill essential respects the botruc- 

 nides found by van Beneden 6 in three genera of pelagic Cerian- 

 thid larvae. The third species resembles very closely the Euro- 

 pean C. mi mbranact us in structure, differing only in the arrange- 

 ment of the mesenteries in the region of the siphonoglyph and 

 possibly also in color, concerning which no notes are at hand. 

 Provisionally, we have named this species ('. johnsoni. 7 



Pam. Cerianthidae. 

 Aetiniaria with long cylindrical bodies, without foot disk, 

 invested by non-adherent tube formed largely of discharged 

 nematocysts ; with tentacles of two orders, marginal and labial, 

 approximately one of each to each intermesenterial space; with 

 numerous unpaired mesenteries, developing, after first eight, in 

 the median intermesenterial space opposite the single siphono- 

 glyph; with strong ectodermal musculature in body wall. 



Gen. Cerianthus Delle Chiaje, 8 1832. 

 With the characters of the family. 



C. aestuari, n. sp. 



This species is abundant on the sandy mud flats, between 

 tides, in False Bay. a shallow, narrow-mouthed inlet cut off by 

 ji neck of beach and sand dunes from the sea just north of San 

 Diego. California. Here it is associated with another burrowing 

 anemone, Harenactis attenuata," and the hydroid Corymorpha 

 palma; 10 all are apparently restricted to Southern California. 



Projecting shortly beyond the level of the sand, from a tube 

 whose mouth measures about 8mm. in diameter. ('. aestuari 

 spreads its outer tentacles in quiet pools to the extent of 10 or 

 12cm. The number of these tentacles, which are in a single 

 cycle, is small, never more than 34, usually about 30. They 



oLes Anthozoaires de la Plankton Expedition. Kiel nnd Leipzig, 1898. 



~l-\>v Dr. II. P. Johnson, formerly connected with the University of 

 California, by whom our material was collected. 



Blstitutioni d'Anatomia comparata. Edit. 1. eon tavole, Napoli, 1832. 



oSee Torrey: Proc. Wash. Ac. Sc. IV. p. 373, 1902. 



i"See Torrey: Univ. of Cal. Publ. Zoology, I, y. 1. 1902; ibid., II, p. 1, 

 l<iii4; ibid., lib p. 253, 1907; .lour. Exp,. Zool., I. p. 395, 1904. 



