198 THE VOYAGE OF H.M.S. CHALLENGEE. 



This specimen was subsequently entrusted hj Sir Eawson Eawson to Sir Wjrvdlle 

 Thomson, together mth two others which he had obtained in 1876, after the publication of 

 Pourtal^s' notice of the first one. Sir Wy ville described the three as follows : ^ " One 

 is very complete in all important points, wanting only the two ' bivial ' arms, but retain- 

 ing the mouth- valves. The second is a little larger ; it wants the mouth-valves, and 

 again the bivial arms ; and with Sir Eawson Eawson's sanction I boiled this specimen 

 down to figure and describe the separate parts. The third specimen is quite perfect, 

 the arms closely curled in in their normal position when contracted; but it is very young, 

 only about 8 mm. in height. Besides the four examples mentioned, I am aware of only 

 another which I have not yet seen ; it was shown at the Philadelphia Exhibition, and 

 was afterwards bought by the Museum of Comparative Zoology at Cambridge, Mass." 



The second of these seems to have been the original specimen described by Pourtales, 

 from which the oral plates or mouth- valves had dropped away ; and as it was gradually 

 falling to pieces from natural decay. Sir Eawson Eawson allowed it to be dissected. 

 The figures on PL III., with the exception of fig. 2, and figs. 1-4 on PI, V., show the 

 results of this process. Fig. 2 on PI. III. is a slightly idealised view of the interior of 

 the cup, so as to show the oral plates of the large specimen represented in PI. 11.^ This 

 was supposed by Mr. Murray to belong to Sir Eawson Eawson, and as it corresponds 

 to No. 1 of Sir Wyville's list, I quite imagined this to be the case ; but Sir Eawson 

 Eawson does not recognise it as his, and I conclude therefore that it is the mutilated 

 dry specimen which Prof Agassiz informs me was sent by him to Sir Wyville with 

 permission to 'cut it up for details. In like manner Sir Eawson Eawson thinks it 

 possible that the original of PI. IV. may be his young specimen mentioned by Sir 

 WyvUle as only about 8 mm. in height, but as Prof Agassiz tells me that he also sent 

 Sir Wyville a small individual, I fear that two specimens have somehow been mislaid. 

 The one which was shown at the Philadelphia Exhibition, and subsequently bought by 

 the Museum of Comparative Zoology, is the original of PI. I. 



It was obtained by Mr. AVilderboer, the collector for Sir Eawson Eawson, after the 

 latter gentleman had left Barbados, and having come into the hands of Prof Agassiz, 

 it was sent by him to Sir Wyville Thomson, together with the Holopus material obtained 

 during the dredging expeditions of the " Blake." This consisted of (l) the very youuo- 

 individual shown in PI. V. figs. 9, 10; Cruise of 1877-78; Station 22, 100 fathoms; 

 ofi" Bahia Honda, lat. 23° 1' N., long. 83° 14' W. ; temperature 71° F. (2) The single 

 ray shown in PI. Vb. fig. 4. This was preserved in spirit, and the greater part of it 

 was subsequently cut into sections. Cruise of 1878-79; Station 157, ofi" Montserrat, 

 120 fathoms. 



1 On the Structure and Relations of the genus Holopus, Proc. Eoy. Soc. Edin., 1877, p. 407. 



- I did not find this out until too late to alter the notice of the oral plates of Holopus, which appears on p. 95. 

 See p. 208. 



