REPORT ON THE CIRRIPEDIA. 133 



Tierra del Fuego up the west coast of America to Peru ; Verruca spengleri, Darwin, from 

 Madeira; and Verruca nexa, Darwin, from the West Indies. Besides Verruca stromia, 

 • ». F. Midler, another fossil species has been discovered since the appearance of Bosquet' 

 Monographie des Crustaces fossiles du Terrain Cretace' du Duche* de Limbourg, 1 viz., 

 Verruca prisca, Bosquet, wliich was found also in chalk in Norwich. As far as my know 

 ledge goes, no descriptions of new species have Keen published since the appearance of 

 Darwin's Monograph. On six different occasions H.M.S. Challenger collected specimens 

 of this genus. They are, no doubt, some of the more interesting forms of animal life 

 collected during the expedition: in the first place, because the}- show that the number of 

 species of this genus is far greater than it has hitherto been thought ; in the second place, 

 because they show that the genus has a true world-wide distribution : of the six Stations 

 which yielded Verruca, one belongs to the Northern Atlantic, three to the Southern 

 Atlantic, one to the Pacific, and one to the Malay Archipelago; in the third place, 

 because the range in depth of the genus is greatly extended by them, the depths inhabited 

 by the six Challenger species being respectively 500, 520-630, 1050, 1425, 1525, and 

 1900 fathoms, whereas the greatest depth from which Darwin knew specimens of Verruca 

 stromia to have been taken was only 90 fathoms; in the fourth place, because these 

 new species form together a very distinct and characteristic division of the genus, show-inn 

 affinity to Verruca nexa, as far as regards the perpendicularity of the walls, and the 

 presence of a distinct third articular ridge on the outer surface of the scutum. In the 

 latter respect they come also near to the fossil Verruca, prism. 



As I pointed out already in the first chapter of this report, in the case of Verruca, as 

 well as in that of Scalpettum, there is coincidence of great antiquity with the occurrence at 

 a considerable depth. However, as there are also known species inhabiting rather shallow 

 water, there should not be attached too much value to this. 



The specimens collected during the cruise of H.M.S. Challenger in some respects 

 closely resemble each other. I will describe them, however, as so many different specie-. 

 though perhaps future investigations may show that, at least some of them, must be con 

 sidered as local varieties of one and the same species. 



For the determination of the species of this genus I have composed the following 

 table: — 



Verruca. 



I. shell much depressed, irregularly circular. 



i. Under si Je of the movable scutum with a prominent adductor ridge, Verruca spengleri, Darwin. 

 ii. Under side of the movable scutum with a slight depression for the 

 adductor muscle. 

 («) Lower articular ridge of the movable scutum not half as 



broad as the upper articular ridge, .... Verruca utromia, O. F. Miiller, sp. 



(/-) Lower articular ridge broader than the upper articular ridge, . Verruca laevigata, <'■. Ii. Sowerby. 



1 Bosquet, Monographic des Crustaces fossiles du Terrain Cretacd de Limbourg, 1 ■>■">:}. 



