Narrative of Bahama Expedition. 163 



seemed to be ^f. iiodcihis Reeve, M. fiilzr:>rciis Sowerby. and 

 3f. po)]iitni Gmel. ^ 



The class Scaphopoda was represented by a beautiful 

 Doifdl/iim, probably 1). hu/iiailiiiu Verrill. This is a white 

 species, less curved than many of the genus, and marked with 

 deep longitudinal fluting. 



A remark made by Dr. Dall, to the effect that hermit crabs 

 which inhabit straight shells are themselves bilaterally sym- 

 metrical, is illustrated by a little hermit which had taken up 

 its abode in one of these tube-like structures of the Deuta- 

 liuDi. Upon removing the crab, it was found to be as straight 

 and symmetrical as any normal Crustacean. 



The reason for the beautiful surface ornamentation of many 

 of the deep-water mollusksis not plain. It seems unlikely 

 that the light produced by phosphorescence or otherwise 

 could make it possible for these beauties to be seen, even if 

 the molluscan eye were capable of such discernment. A cer- 

 tain beauty is of course imparted to these shells by their very 

 delicacy, but the purely superficial lines and bead-like orna- 

 mentation is beautiful, aside from any quality of texture. 

 Perhaps the best suggestion bearing on this point is made by 

 Dr. W. II. Dall in the admirable discussion with which he in- 

 troduces his report on the Mollusca of the "Blake." He says: 

 •' Much of the sculpture which is presented by the deep-sea 

 species is particularly beautiful from its delicacy. There 

 seems to be an especial tendency to strings of bead-like 

 knobs, revolving stria^ and threads, and delicate .transverse 

 waves. It is particularly notable that many of the deep-sea 

 forms, among all sorts of groups indifferently, have a row of 

 knobs or pustules following the line of the suture and imme- 

 diately in front of it. The representatives of the rock-purples, 

 or Murices, a group which in shallow water frequent the" 

 rocks and stony places, and are then strongly knobbed or 

 spinous, retain a similar character in the deeps, but the pro- 

 cesses in question are extremely delicate or foliaceous, instead 



^ The author is here, as elsewhere, indebted to Mr. II. F. Wickham for 

 the preliminary and approximate identification of Mollusca. 



