REPORT ON THE CEPHALOPODA, 231 



From the above table it will be seen that (excluding the type form, concerning 

 which no information has been published in this regard), not one of the species of 

 Cirroteuthis has been found at a depth less than 600 fathoms, and, therefore, if we are 

 justified in taking the depth to which the dredge or trawl descended as representing the 

 depth from which the specimens were obtained, we must certainly regard them as deep- 

 sea forms. 



It is, however, well known to all who are familiar with the methods of deep-sea 

 dredging that this cannot be at once assumed. Indeed, in one case, namely that of Cirro- 

 teuthis pacifica, the MS. Station Book kept on board the Challenger states that the specimen 

 came from the surface, but it appears certain that this was merely an assumption based 

 upon the supposed nature of the animal, and cannot be held as conclusive evidence in 

 regard to the occurrence of these animals on the surface. 



On the other hand, it is not a little noticeable that this family should have remained 

 among the greatest of zoological rarities until deep-sea dredging was practised, a,nd that 

 then specimens should have been procured with comparative frequency. Negative 

 evidence is proverbially unsatisfactory, but had they been surface organisms one would 

 have expected that the voyages of the older zoologists would have shown us some trace 

 of creatures which are too remarkable to have been passed over in silence had they 

 been observed. 



The fact that the animals in question should have been so long known from one 

 locality in the Arctic regions is probably to be explained, as v. Willemoes-Suhm 

 has hinted, by this being one more instance of a type found in the abyssal regions 

 near the equator and in temperate regions of the globe, whilst it approaches near 

 to the surface in the Polar regions (see p. 65). The probability that this hypothesis is 

 correct is increased by a consideration of the temperatures of the various localities at 

 which the spe(;imens were found ; a glance at the table shows that while the surface 

 temperature in these various places varied as much " as from 43° to 80° F., the 

 bottom temperature was comparatively constant, ranging between 3.5°"6 and 41°"8 F. 



Furthermore, eggs containing embryos undoubtedly belonging to this genus have 

 been dredged by Professor Verrill in deep water, 428 to 1106 fathoms, and it would seem 

 unreasonable to suppose that animals living at the surface should lay eggs and leave 

 them to sink through so great a distance, during which time they would be exposed to 

 great danger from the attacks of their enemies. 



The two other genera discovered by Professor Verrill do not seem to be so certainly 

 deep-sea animals as Cirroteuthis, for they have both been met with at depths of less 

 than 300 fathoms, although they appear also to range to a depth of over 1000 fathoms. 



In discussing this matter it must not be forgotten that there are animals with a very 

 extensive bathymetrical range, e.g., Amphilepis norvegica, among the Ophiuroidea, and 

 Bathyactis symmetrica among the Corals, but these are exceptions, and from the reasons 



