Mr. II. J. C'art.T on the Nomenchiture uf (ht Tctlivaili-. ]o;', 



thyadjB in situ, it slumid be iTiiicinLcred that there arc no 

 aiK-lior-hoad.s at all in 7'. ca.siihi, and that where (in most of 

 the sj)ecir.-() they are present they .ire as ])Ientit'ul in the upper 

 portion and free surface of the body of the Tethya as in any 

 other part ; while in tin- fixed or sessile form of T. arahica 

 the base of this hemisjdierieal sponge is agglutinated to the 

 rock by a layer of horny sareode ; and therefore it is pro- 

 bable that the agglutination of the spicules in the conical ex- 

 pansion of T. casnla to the sand serves to fix it there as much 

 as the spicules. 



The minute bihamate and contort C- and S-shaped s])icules, 

 with which the sareode of the head in T. casula is densely 

 charged, tinds its equal in every respect in T. cranium (Bower- 

 bank, Brit. Spong. vol. ii. p. 85) and in T. arahica {I. c). It 

 is also ])resent in like manner in T. atrojmi-purea (Annals, 

 1870, vol. vi. p. 176, pi. 13), but larger and spinous towards 

 the extremities. It, together with the anchor-headed spicule, 

 might have existed in T. daefj/Ioidea {ib. 1869, vol. iii. p. 15); 

 but, unfortunately, 1 had given the specimen to Dr. Bower- 

 bank before I saw the desirableness of examining it more 

 minutely. 



So the presence of this minute spicule would appear to be 

 characteristic of the Tethyadre generally ; for it is mentioned 

 by Schmidt in TetiUa poJi/ura (Atlant. Spong. Faun. 1870, 

 p. 66), although it is unnoticed in his passing observations on 

 TetiUa euplocamus (Spong. iVlgier. 1868, p. 40, and Atlant. 

 Spong. Faun. p. 66), which came from Desterro, on the coast 

 of Brazil, and, having no separate description allotted to it, 

 may have had no special examination. 



Why Sciimidt should have changed the name of Tetliya to 

 TetiUa (Atlant. Spong. Faun. p. 60, TetiUa cranium) and have 

 retained it for the sponges of which Tetliya lyncurium is the 

 type, I am at a loss to conceive. 



Nomenclature of the Tetliyadoi. 



In 1750 Donati* introduced the word '^ Tetie " for that 

 sponge to whicli, among others, Lamarck, in 1802, gave the 

 name of Tethya lyncurium'f. 



Risso, in 1826, first nsed the name of Tethya craniumX, 

 which was applied to the British species by Fleming in 1828§. 

 In 1833 Nardo introduced the term oi Donatia aurantium for 



• Nat. Mar. dell' Adriat. G4, tav. 9. fig. a, b, &c, (ap. Johnston). 

 t Ann. du Mus. t. i. p. 71. no. 5 (ftp. Blaiuville, Man. Actiuol.). 

 X L'Europ. M^rid. vol. v. p. 3G4 (ap. Johnston). 

 § Hist. Brit. An. p. 519 {ibidem). 



