24 THE VOYAGE OE H.M.S. CHALLENGER 



The single specimen is very much worn, but the shell appears to possess concentric 

 lines of growth furnished with minute black tubercles ; along the jugum these are either 

 absent or worn away ; lateral areas scarcely defined. Ground colour buff, dark at the 

 sides, and streaky on each side of the pale jugum. • 



The girdle is covered with a close covering of very short mixed black and white spines, 

 in which a banded arrangement can be discerned, a darker band corresponding to each 

 valve ; there are also numerous large stout blunt spines, which are usually white in colour, 

 but may be black tipped with white. 



In a specimen from New Ireland in the Science and Art Museum, Dublin, there is a 

 similar banded arrangement of very small spicules, but the larger ones are of considerable 

 size, being 3 mm. in length, arcuate, and white in colour. The animal itself is 65 mm. 

 in length, and 35 mm. in breadth. 



The Chiton aculeatus of Quoy and Gaimard is clearly this species. The authors 

 describe two varieties, the one (A.) with short obtuse, closely set spines, and ligament with 

 eight black bands ; the other (B.) with long sharp scattered green spines. The anterior 

 valve with nine to twelve (var. A.) striated teeth, the posterior with eight. The under 

 surface of the valves with a brown jugum ; the remainder is horn-coloured, with a " burnt 

 spot " (tache brulee) at the angle of the apophyses. Length 4 inches 6 lines, breadth 2 

 inches, but there are larger. This species is found in New Zealand, New Guinea, and New 

 Ireland. Var. A. is from Tongatabou and Port Dorey, New Guinea. The var. B., 

 which evidently is the same species as that mentioned above from New Ireland, appears 

 to be a well-marked form. 



In his MSS. Carpenter states that " Acanthopleura granata, Reeve (no locality), is a 

 worn specimen of Acanthopleura borbonica, Desh. ; and Acantliopleura macgillivrayi, 

 A. Ad. (no locality), is perhaps only a fine Acanthopleura piceus, Reeve, Acanthopleura 

 borbonica, Desh., &c, and very close to Acanthopleura brevispinosa, Sow." 



I am indebted to my friend, the Rev. H. M. Gwatkin of Cambridge, for a couple of 

 specimens of Acanthopleura sp. (?) from Aden in the Red Sea, which undoubtedly belong- 

 to the Acanthopleura, spiniger series. The shell is much more delicate than in the other 

 species of the genus with which I am acquainted. The surface is evenly studded with 

 very small concentrically disposed black tubercles ; the colour appears to be a uniform 

 dark brown or black ; lateral areas obsolete. The under surface of the valves has some 

 points of interest. There are ten slits in the auterior valve, long teeth, short eaves, the 

 colour is brown, the jugum being of a darker colour. The intermediate valves are greyish, 

 or brownish grey behind, the jugum dark brown in colour, and the sutural laminae 

 are grey, tinged with madder brown. The posterior border is less peaked than in Acan- 

 thopleura spiniger (type), and consequently the reflected portion of the tegmentum 

 encroaches less on the under surface ; in this respect and in the general appearance of the 

 under surface the intermediate valves somewhat resemble those of Acanthopleura granu- 



