418 Mr. H. J. Carter on a new TetIiyay/-om Shetland. 



is generally the case. There are no bihamates. Average 

 length of longest spicule, which is the anchor-headed shaft at 

 the base of the Tethya^ about 5-12ths of an inch. Size of 

 specimen, viz. fig. 1, about 2 inclies high by If inch broad. 



Hah. Marine ; deep water. 



Log. Sea about the Shetland Islands ; Haaf Banks. 



Ohs. I have assumed that this species comes from the 

 Haaf Banks, seeing that the label on the jar bears the words 

 "Shetland. J. S. Bowerbank," with '"'' Tethya Jyncurium^^ 

 written, as before stated, in Dr. Bowerbank's hand, who, in 

 his ' British Sponges,' vol. ii. p. 84, as before stated, observes, 

 with reference to T. cranium : — " I obtained nearly three 

 hundred specimens of this sponge from the Shetland deep-sea 

 fishermen, through their agent," part of which, viz. the two 

 specimens of T. cranium and four of the species just described, 

 in the jar at the British Museum, I further assume to have 

 belonged to that collection. " Tethya lyncurium''^ {Donatia^ 

 Nardo & Gray) does not appear to have been yet found north 

 of Connemara Bay, in Ireland, viz. lat. 53" 26' (Johnston, op. 

 cit. p. 85). 



T. zetlandica is closely allied to T. cranium in most ways. 

 It appears to inhabit the same locality, and sometimes, in like 

 manner, to grow in the cavity or on the stem of Halichondria 

 ventilahriim^ Johnst. (see illustrations of both species, PI. 

 XXII.) ; but it markedly differs from T. cranium in two points, 

 viz. in the disposition of the spicules on the surface, and in 

 the absence of bihamates. This is at once seen in fig. 9,^here 

 the hoary, shining, asbestine appearance of the spicules of T. 

 cranium, arranged in whorls like the hair of the human head, 

 parting from the crown, from which Johnston has aptly named 

 it [op. cit. pi. 1. fig. 1), contrasted with the irregular disposi- 

 tion of the same in T. zetlandica (fig. 2) , at once points out the 

 two species ; while the entire absence of bihamates (fig. 9, c) 

 in the sarcode (which is pregnant with them in T. cranium) is 

 a not less distinguishing microscopic character, in which T. 

 zetlandica agrees with T. antarctica. And not only, as before 

 stated, are these differences to be seen in the adult forms, but 

 they equally characterize the still unborn Tethyce of the 

 interior in each species (figs. 11 & 12). Thus the spiral twist 

 of the spicules and the presence of bihamates, though all very 

 minute, in the young Tethyce of T. cranium, are as charac- 

 teristic of it as the opposite is characteristic of T. zetlandica. 



For the purpose of illustration, I have given figures of two 

 specimens of T. zetlandica, in one of which the papillae are 

 large and separate (fig. 2) and in the other small and almost 

 confluent (fig. 1) ; the latter, as will be observed, has grown 



