4o6 



COELENTERATA ANTHOZOA 



CHAP. 



species of Upizoanthus form colonies on the shells of G-asteropods 

 inhabited by hermit crabs. Parazoanthus tunicans is found on 

 the stem of a Plumularia ; Parazoanthus separatus, from Jamaica, 

 is associated with a sponge. The base of the bundle of long 

 spicules of the Sponge Hyalonema (p. 204) is almost invariably 

 sheathed by a colony of Upizoanthus stellaris. 



The only genera occurring within the British area are 

 FjnzoantJms (with six species), Parazoanthus (with four species), 

 and Zoanthus sulcatus. 



Of the species of Upizoanthus, P. incrustatus is fairly common, 

 in depths of twenty to eighty fathoms on all our coasts, and is 



frequently commensal with 

 different species of hermit 

 crabs, while P. paguriphilus 

 is found in much deeper 

 water off the west coast of 

 Ireland and is always com- 

 mensal with hermit crabs. 

 Parazoanthus anguicomus is 

 found at depths of a hundred 

 fathoms off the Shetlands 

 and west of Ireland, and is 



Fig. 177.— Zoanthus macffillivrmji, a small usually associated with Vari- 

 colony. The tentacles are shown some- <=r)ppipq of Snonapd 



what contracted by the preservative. Each °^^^ SpeClBS 01 SpongeS. 



zoold is about 25 mm. in length. (After Gerardia savalia is the 



largest " black coral " of the 

 Mediterranean. The colony begins by encrusting the stem of 

 one of the Gorgoniidae, but soon surpassing its support in 

 growth, it forms a basal horny skeleton of its own and builds 

 up very large branching colonies. A specimen in the British 

 Museum,^ from twenty fathoms off the island Negropont, is two 

 metres high and two metres wide. The genus appears to be 

 related anatomically to Parazoanthus. 



Fam. 2. Zaphrentidae. — This family of Palaeozoic corals is 

 usually placed with the Turbinoliidae or in the separate group 

 Tetracoralla. Eecently Duerden ^ has given reasons, based on 

 the method of increase of the septa in Lophophyllum,, for believ- 

 ing that their affinities lie rather with the Zoanthidae than 



1 F. J. Bell, Trans. Zool. Soc. xiii. pt. ii. 1891, p. 87. 

 2 J. E. Duerden, Ann. Mag. Nat. Hist. (7) ix. 1902, p. 381. 



