66 THE VOYAGE OF H.M.S. CHALLENGER. 



It is impossible to accept the identification of this species with Trochus lineatus, Da Costa 

 ( = Trochus crassus, Pult.), a British and Adriatic shell, or with Trochus variegatus, Anton, from the 

 Cape of Good Hope, or with Trochus sagittiferus, Lam., also from the Cape, or with Trochus 

 turbinatus, Born. (= tessellatus, Gmel.), a Mediterranean 1 species, or with Trochus articulatus, Lam., 

 also a Mediterranean form. I am far from saying that some or all of these may not be the 

 same ; I only say that no sufficient evidence of transitional forms lias been produced to justify their 

 union. 



I regret further to be unable to accept the identification of this species with Trochus citrinus, 

 Gmel., which both Philippi (Conch. Cab., ed. Krister, p. 290, see pi. xlii. figs. 12, 13) and Fischer 

 loc. cit. sup) approve. That species, according to Gmelin, belongs to Asia ; the description he gives 

 of it" is insufficient for determining any species, and is in some points as little applicable to the 

 Madeiran species as it could well be ; finally, the figure he quotes from Knorr (Vergniigen d. Augen, 

 vol. i. p. 16, pi. x. fig. 7) presents a back view of a shell, and is beyond recognition. All this 

 indeed Dr Fischer admits, for he says, " Rien ne prouve . . . 1'identite du type de Philippi avec le 

 type de Gmelin," adding, " il m'est impossible d'identifier convenablement le type de Knorr." 

 This last point presents precisely the difficulty which seems really insurmountable, since everything 

 depends on what Knorr's species really was, and that cannot be ascertained. 



In looking about, then, for a name, Trochus listeri,Wood, presents itself. It is figured in Wood's 

 Ind. Test. Suppt. (ed. Hanley), p. 219, pi. v. fig. 8. It is not unlike the species we are examining ; it 

 is said to come from Madeira, where there is no other species it can be, and the type specimen is 

 said to be in the British Museum. Were this last statement correct, Wood's name might possibly 

 have found acceptance, but Mr Edgar Smith assures me there is no such shell to be found in the 

 British Museum. Such being the case, Trochus listen, which has not a single word of description, 

 and only such a figure as the Index offers, is beyond identification. 



There is really, then, no other name than that of Gould ; and though his figures are far from good, 

 yet, taking along with them the description he gives, and the locality to which he attributes his shell, 

 no doubt can remain that Trochus colubrinus is the species from Madeira that has been so sorely in 

 want of a name. 



I have quoted Mr Lowe's name as that by which it has been locally known for many years — 

 one, too, which very strikingly recalls the enormous use of the animal by the common people as an 

 article of food, and the consequent presence of the rejected shells everywhere in town and country. 

 Unfortunately Mr Lowe's name was never published. 



The finding of the species at Santa Cruz, Tenerife, is a fact worthy of notice. There are in the 

 Challenger collection five immature specimens quite unmistakable. It is on the strength of these 

 that I have quoted D'Orbigny (loc. cit. sup) as having this species in view under the name of Trochus 

 crassus, " Matton and Rackett." I am not aware of any one else having quoted it for the Canary 

 Islands, and I do not remember to have myself found it either at Canary or at Tenerife. This fact, 

 however, I am unable to verify, as the restraints of narrow accommodation make my Canarian 

 collection quite inaccessible. 



1 Dr Fischer (Kiener, p. 202) adds, " Canarian " tn the authority of M'Andrew ; but I have failed to find 

 any authority in M'Andrew for the statement. 



2 Trochus testa conico-convexa, citrina, lineis angulatis nigris picta : anfractibus duobus primis fusco 

 obumbratis. 



