COLLINGE : ANATOMY OF SLUGS. 8l 



some of the duplicate specimens which were collected on the "Galatea 

 Expedition" in 1846, and I have here given two figures of the same 

 (PI. iv, figs. 4 and 5). 



A comparison of the " Galatea " specimens with those from 

 Chekiang, and those from the Hawaiian Isles, shows many external 

 points of difference, thus in the " Galatea " specimens the ground 

 colour is a yellowish-brown and there are three distinct lines o a 

 deeper brown, one in the mid-dorsal line and a lateral one on each 

 side of this. In the British Museum specimens from Chekiang, and 

 in those from the Hawaiian Isles, the median line is absent, or only 

 very faintly represented, while the lateral ones are very irregular, 

 broad, lines with numerous spots and blotches on a yellowish ground. 

 In all three cases the jaw is ribbed and anatomically they are practi- 

 cally identical. This being so, the description given by Bergh is 

 quite inadequate for the species, for so far as external colouring and 

 markings are concerned, it is a most variable one. 



Although differing externally as shown above, all three agree so 

 closely anatomically, that at first I was inclmed to group them all 

 under T. australis, Bergh. A later examination, however, of the ex- 

 ternal characters of the specimens above mentioned, suggested to me 

 the possibility of certain specimens in the Bricish Museum Collection 

 being also referable to T. australis, Bergh, thus I was led to make a 

 very careful examination of what at first appeared to be a series of 

 closely allied species. 



The results of this examination leave no doubt in my own mind 

 that they nmst all be referred to the T. hilineatus, Bens., (i) which 

 was described in 1842, and its anatomy described and figured by 

 Keferstein in 1866 (12). 



The specimens in the British Museum collection which were ex- 

 amined are as follows : 



T. hilineatus, Bens. 



Benson's original description is very brief but sufficient to identify 

 the species. There are two examples in the Collection, one from 

 Chusan, the other from Yokohama, Japan, from the " Challenger " 

 collection. Cockerell (5) has named this latter T. confusus from the 

 fact that it differs from Benson's species in possessing a jaw which is 

 not ribbed. At the same time he admits that it is like von Martens' 

 figure of T. bilirieatus (13), and also like Keferstein's figure {op. cit. 

 T. i, fig. 5). Now Keferstein's account of the internal structure agrees 

 in the main with that I have given here in rather greater detail, so I 

 think, there can be no question as to Cockerell's T. confusus and 

 Keferstein's T. hilineatus being identical, and I shall show that the 



