TETHYA. 43 



TETHYA CRANIUM, -car. 5, INFKEQUENS, Carter, Ann. 

 Nat. Hist., ser. 4, vol. xviii, 1876, p. 405; 

 pi. xvi, figs. 48 a c. 



Porrecto-ternate spicula, of remarkable form, the 

 prongs being distally truncated and slightly expanded, 

 so as to form a cup-shaped excavation bordered by a 

 serrated margin, while the central canal of the spi- 

 culum on reaching the bottom of the cup-shaped 

 cavity divides into a number of minute branches, one 

 of which passes to each of the tooth-like processes on 

 the margin of the cup. The recurvo-ternate spicules 

 have the arms much more divergent, and not so re- 

 curved as in the normal T. cranium; and the usual 

 bihainate flesh-spicules are altogether absent. This is 

 certainly a most remarkable form. 



One specimen, " Porcupine ' Expedition, 1869, No. 

 57, Lat. 60 14' N., Long. 6 17' W., 632 fathoms, in 

 the deep mid-channel between Scotland and Faroe. 



Tethya cranium, Phakellia ventilabrum, and Isodictya 

 infundibuliformis, are all brought up in great abundance 

 by the hooks of the Shetland long-line men, when 

 fishing for torsk and cod on the Haaf Banks. 



When Dr. Bowerbank first commenced the study of 

 British Sponges, the Tethya, &c., were considered 

 extremely rare. Desirous of possessing these fine 

 species, he wrote to the fishermen's agent at the Out 

 Skerries, and said he would give sixpence each for all 

 that he could procure. No doubt our old friend 

 thought the offer an uncommonly safe one ; but in a 

 short time a huge keg of Sponges came (300 Tethya, 

 see n, p. 84, among them !), and a nice little bill of 



