346 



margin on both sides, and with one to three shorter ribs between each pair 

 of the longer ones. In the figure of this specimen, however, the tubercles 

 are represented as obscure and ill defined on some of the ribs and as quite 

 obsolete on the others. 



Pachydiscus (Haradai ? var.) perplicatus, 



Plate 48, fig. 1. 

 Shell apparently very similar to that of P. Haradai in general form, but 

 with its surface marked by much larger and more prominent transverse 



ribs, or coarse rib like folds, 

 with more deeply concave 

 grooves between them. 

 The only specimen that the 

 writer has seen is a well 

 preserved cast of the inte- 

 rior of the shell of a speci- 

 men, with a little more 

 than the whole of one side 

 worn away, except at A, 

 where part of the siphonal 

 region is preserved. The 

 portion that remains is 

 about six inches and a half 

 in its greatest diameter, 

 and the specimen, when 

 entire, was probably rather 

 more than seven inches in 

 diameter. Its outer volu- 

 tion is marked by fourteen 

 long and slightly flexuous, 

 simple ribs, or rib-like folds, with usually one, but occasionally two, 

 shorter ribs intercalated between each pair of the longer ones. These 

 latter are narrowest, most prominent and abruptly truncated at the 

 umbilical margin, but broader and not so prominent on the periphery. 

 The six nearest to the aperture average from a little less than an inch to 

 an inch and a quarter apart, measuring from the middle of their summits 

 and near to the periphery. Septation unknown. 



Comox Eiver, near Comox, V.I., J. R. Bennett, 1896 : one specimen, 

 which he has kindly presented to the Museum of the Survey. 



Some of the long ribs seem to bear a low, conical, and transversely 

 elongated tubercle on the umbilical margin, but this appearance is partly 



Fig. 22. — Pachi/discus (Haradai? v&v.) perplicatus. 

 Outline of transverse section of the outer volution, 

 at A, the only place where any part of the 

 siphonal region is preserved, and httiveen the ribs, 

 of the specimen from the Comox River represen- 

 ted on Plate 48. 



