sponge-fauna of Norway. 149 



individuals have become united into individuals of a higher 

 ordei" ; in Pachymatisma single individuals have become more 

 complicated by a branching or budding off of main excurrent 

 canals, which are here to be regarded each as an individual of 

 a lower order ; in Cydonium we appear to have a case of lipo- 

 stomism, the functions of an osculura being vicariously carried 

 on by the poriferous chones. 



Indicating the individual expressed by a single excurrent 

 chone by the symbol 1, and that expressed by a single main 

 excurrent canal by i, we may briefly formulate the relations 

 of the four genera in the following diagram : — 



Isops 1.1.1.1.1.1.1. 



Geodin (Ill) (1111) 



Padiymatisma 0.0.1.0.0.0.1 



1. I. I. I.I I. I. I. I. I 



Cydonium ? No obvious individuality beyond that 



of the entire stock. 



Distribution. Kors Fiord, Norway, Station 23 : 180 fathoms. 



Bowerbank cites this sponge from Torquay, south coast 

 of Ireland, Orkneys, and Wick, Scotland. We now have it 

 from Norway ; and Grube describes it, as pointed out to me 

 by Mr. Norman, under the name of Caminus osculosus from 

 St. Malo. It thus extends from Norway and the Orkneys on 

 the north, to St. Malo on the south, and as far west as the 

 Guliot caves on the south coast of Ireland ; bathymetrically, 

 it ranges from low-tide level to 180 fathoms. 



Group Tetillina {Tjethtina) , Carter. (PI. VII.) 

 Genus Tetilla, 0. S. 



Tetilla cranium, Miill. 



1789. Akymimm cranium, Miill. Zool. Dan. t. 85. f. 1. 



1815. Tetkya cranium, Link. Mem. d. Mu.s. i. p. 71. 



1816. Alcyonium cranium, Lnix. Ilist. d. Polypes, p. 347. 



1818. S2wn(/ia jnlosa, Mont. Mem. "VVeru. Soc. vol. ii. p. ll'J, pi. xiii. 



tigs. 1-8. 

 1828. Tethya craniimi, Flem. Brit. Animals, p. 519. 

 1834. Tethya a'anium, Blainv. Mem. d'Act. p. 544. 

 1842. Tethea cra7iium, Johnst. Brit. .Spong. p. 83, pi. i. figs. 1-8. 

 1864. Tethea craniimi, Bwk, Monog. Brit. Sp. i. p. 182, pi. xxxi. 



tig. 362. 

 1866. Tethea cranium, Bwk. Monog. Brit. Sp. ii. p. 83. 



1866. Tethya cranium, O. S. Adriat. Spong. ii. Suppl. pi. i. fig. 14. 



1867. Tethya cranium, Ciray, 1'. Z. 8. p. 543. 



1870. Tetilla cranium, O. S. Spong. All. p. 66. 



1871. Tethya cranium, Carter, Ann. & Mag. Nat. llist. vol. viii. p. 104. 



