256 



2. Ophiozona capensis. (PI. I., Figs, i and 2). 



No tentacle-scales to most of the ossicles, three or four 

 minute spines, and moderately sized, irregularly shaped radial 

 shields. 



This diagnosis will show that Ihe Cape Ophiozona is distinct 

 from those enumerated by Mr. Lyman in his " Challenger " 

 report, while the species lately described by Professor Koehler 

 has two tentacle-scales along the whole length of the arm. 

 That which intrigued me most was the disposition of the 

 tentacular pores on the arms ; they are limited to the three 

 proximal joints, are quite large, and are protected by several 

 scales each ; this is a very abnormal arrangement among 

 Ophiuroids, and is, so far as I know, only known in the appar- 

 ently distant genus Ophiolipus ; in spirit preserved specimens 

 there are no signs of podia ; in his definition of Ophiolipus Mr. 

 Lyman says merely " tentacle pores only at the basal under arm 

 plates," and makes no reference to the presence or absence of 

 podia. 



The comparatively large size of the pores in this species and 

 the apparent absence of podia may, in general terms, be trans- 

 lated into the statement that the respiratory apparatus is not 

 diffused along the whole arm as in most Ophiuroids, but 

 localised ; if this is true, it would follow that we should expect 

 to find haemoglobin or some other oxygen-bearing compound ; 

 haemoglobin was, of course, detected several years since by 

 Foettinger in Ophiactis virens. The resolution of this question 

 is not possible for me with the preserved specimens which I have, 

 but it could easily be settled by naturalists on the spot ; and it 

 1? one which I should very much like to see investigated. 



I may be allowed to remark that the typical arrangement of 

 the podia on the arms, as described in text books, is probably 

 very often altered ; we know now of two genera, not apparently 

 closely allied, in which the proximal pores are alone retained ; 

 scattered through the writings of the describers of brittle-stars 

 there are indications of variations, which, had the writers been 

 morphologists, rather than systematists, they would have dilated 

 on. 



Put in general terms, it may be said that a comparative in- 

 vestigation of the disposition of " tentacle-pores " and " tentacle- 

 scales " promises to be of great interest. 



