LATER YEARS 411 



by other distractions : " I have been to see most of my 

 friends," he writes, "and am quite in the swim." The 

 Panamic Echini was published the following November : 

 it contains a description of the Echini collected on the 

 Albatross Expedition of 1891, and a comparison of the 

 Echini found on both sides of the Isthmus of Panama. 

 From the similarity of the species at moderate depths 

 on each side, he concludes that there must have been a 

 free communication across the Isthmus in comparatively 

 recent geological times down to a depth of about one 

 hundred fathoms, while the species of the continental 

 slopes are so similar to the genera of the Cretaceous 

 period that one can assume a depth of at least two 

 hundred and fifty fathoms in Cretaceous times. Fur- 

 thermore the abyssal genera are so closely allied to those 

 of the Jurassic period that a still greater depth seems 

 probable at that time. 



Towards the end of February, 1904, he writes from 

 Paris : — 



" In about ten days I expect to cross over to Lon- 

 don with Max, and spend a few days browsing round 

 in the British Museum over some of the deep-sea speci- 

 mens I want to see again. I 've got a few things to attend 

 to in relation to my next expedition, see the Admiralty 

 people and get all the information possible as to the 

 weather, etc., of a region which is practically unknown." 



Writing from London about the middle of March, he 



says : — 



" I have just come back from the British Museum 

 where I had a few chores left in the way of examining 

 some specimens : that 's now done and I 've really fin- 



