138 THE VOYAGE OF II. M.S. CHALLENGER. 



Four specimens of the species were taken at Station 317, February 8, 1876, lat. 48° 

 37' S.j long. 55" 17' W.; depth, 1035 fathoms; bottom temperature, L°7 C; bottom, 

 hard ground. 



Observations. As I said when treating of the genus, the deep-sea Verrucce re- 

 semble in some respects Verruca nexa. Darwin. However, of the three strongly pro- 

 minent longitudinal ridges on the scutum of that species, only one (my third articular 

 ridge) is represented in the deep-sea species ; moreover, the strongly-ribbed appearance 

 of the whole shell is wanting in the deep-sea species, and finally, the shape of the valves 

 is different. With regard to the parts of the mouth, we find some corresponding 

 features : the shortness of the palpi of the labrum, the presence of the bead-like teeth on 

 the crest of the labrum, the pectinated condition of the lower part of the mandible, &c. 

 The cirri arc slightly different as far as the length of the rami, &c, is concerned. As I 

 was not able to investigate the same details in all the deep-sea specimens of different 

 localities, 1 cannot say whether they all correspond to one another with regard to the 

 structure of the animal's body. There can be no doubt, however, that the deep-sea 

 species, of which the form I called Verruca gibbosa has been studied most accurately, are 

 different from those which occur in shallow water, and which were described by Darwin. 

 On the contrary, I am by no means sure that the forms which will hereafter be described 

 as different species must really be considered as such. For whilst I shall give a detailed 

 description of one of the other species {Verruca quadrangularis), in the case of the 

 remaining ones I shall only point out the differences which seem to prevent their being 

 described as belonging to one of the other species. Later investigations, made with the 

 aid of a much richer material, wdl perhaps show that the different deep-sea Verrucce are 

 much more nearly related than I could ascertain. 



Verruca nitida, n. sp. (PL XII. figs. 6, 7). 



Shell white and very flat ; surface smooth, with not very prominent growth-ridges. 

 Walls almost perpendicular to the surface of attachment, which being narrow causes the 

 base to be narrow also. Movable scutum relatively large, with a sharply pointed apex : 

 its upper articular ridge can hardly be made out, the third articular ridge, on the contrary, 

 is well developed ; interspace between the third articular ridge and tjie tergal margin 

 narrow. Movable tergum with the apex slightly bowed and blunt. Ajjex of the carina 

 strongly projecting. The carina articulates with the rostrum by means of a single large 

 tooth, which forms part of the latter valve. Immovable scutum divided into two 

 triangular parts forming an angle with each other. 



There is only a single specimen which shows the characters given above. It was 

 taken in the Moluccan Archipelago, and there can be no doubt that it belongs to the 



