CHAP. ILL. ] TENERIFFE TO SOMBRERO. 185 
700 fathoms in another locality, the eye-stalks have lost their 
special character, have become fixed, and their terminations 
combine into a strong pointed rostrum. In this case we have 
a gradual modification, depending apparently upon a gradual 
diminution and final disappearance of solar light. On the other 
hand, M/unida, from equal depths, has its eyes unusually devel- 
oped, and apparently of great delicacy. Is it possible that in 
certain cases, as the sun’s light diminishes, the power of vision 
becomes more acute, while at length the eye becomes suscepti- 
ble of the stimulus of the fainter light of phosphorescence ¢ 
The absence of eyes is not unknown among the Astacide. 
Astacus pellucidus from the Mammoth Cave is blind, and 
from the same cause —the absence of light; but, morpholog- 
ically, the eyes are not entirely wanting, for two small abor- 
tive eye-stalks still remain in the position in which eyes are 
developed in all normal decapods. In Wéllemoesia no trace 
whatever remains either of the organs of sight or of their 
pedicels. 
Two specimens of a species of the genus Leda were sifted out 
of the mud, and two minute gasteropods, one a prettily orna- 
mented species, allied apparently to Solariwm (Fig. 43). These 
Fia. 43.—Solariwm (sp.). Greatly enlarged. (No. 13.) 
and the other deep-sea mollusca will shortly be placed in the 
hands of Mr. Gwyn Jeffreys for determination. Several speci- 
mens were found on this occasion of two bryozoa of the /arci- 
minaria group, which have turned up more than once from 
great depths, frequently in considerable quantity, entangled in 
the swabs or on the outside of the dredge net. They are fre- 
