HEMIASTERIDAE 233 



according to Koehler, are particularly well developed in P. reductus, better so than in the 

 species P. cordatus. The fact that the fascioles in Koehler's figure of P. reductus in side 

 view {op. cit., pi. xvi, 14) seem to have been retouched on the photo, whereas figs. 12 

 and 13 of the same plate, showing the same specimen from above and in end view, do 

 not show any trace of fascioles, might lead one to suggest that some mistake has crept 

 into the representation of the species. Having had an opportunity of re-examining the 

 type specimen in the Paris Museum I can, however, testify to the correctness of 

 Koehler's description and figures. The fasciole has been marked with a black line on the 

 specimen, not on the photo ; but it is quite distinctly seen on the specimen. 



It might, of course, be suggested that fascioles were originally present in the 

 Discovery specimens, but have been reduced in the course of development. If so, one 

 would expect a fasciole to be developed in the young ones ready to leave the marsupium. 

 There is, however, no trace of a fasciole in the young specimens from the marsupium 

 in the present species. These specimens, it may be added, have the globiferous pedi- 

 cellariae typically developed. 



The present species forms a most remarkable parallel to P. reductus ; but the character 

 of the fascioles, entirely absent in one and distinctly developed — though very thin — in 

 the other, shows definitely that the two forms belong to two distinct genera. 



Parapneustes cordatus, Koehler 



(Plate III, figs. 1-4) 



Parapneustes cordatus, Koehler, 1912. IP Exped. Antarct. Frangaise. Echinodermes, p. 165, 



pi. xvi, figs. 15-27. 

 P. cordatus, H. L. Clark, 1917. Hawaiian Echini. Echinoneidae. . . Spatangidae, p. 173. 



St. 181. 12. iii. 27. Schollaert Channel, Palmer Archipelago, 160-335 ^n- 2 specimens. 

 St. 182. 14. iii. 27. Schollaert Channel, Palmer Archipelago, 278-500 m. 4 specimens. 



Only a single, apparently male, specimen of this species was taken by the ' Pourquoi- 

 Pas.?'. Koehler's very careful description of this specimen could thus, of course, not 

 be all that was to be desired and in particular the question whether this species is 

 brood-protecting like most other Antarctic Spatangoids had to be left undecided. It 

 is therefore most satisfactory that the 'Discovery' has secured some specimens in fair 

 preservation, which give not only the solution of the question whether the species 

 is brood-protecting, but also other very important information. 



The specimens, which are all adult, 49-56 mm. in length, agree perfectly with the 

 type specimen in regard to their general shape, only the restriction of the posterior part 

 of the test is sometimes less pronounced. Also in the pedicellariae (particularly those 

 remarkable globiferous pedicellariae with the valves terminating in five long and slender 

 teeth) these specimens agree perfectly with the type. But in regard to the fascioles they 

 differ conspicuously from the type specimen. Whereas this latter had only the peri- 

 petalous fasciole developed, the present specimens also have a latero-subanal fasciole. 

 As a rule the peripetalous fasciole is fairly distinct, but it may be more or less reduced, 

 sometimes more on one side than on the other; the latero-subanal fasciole is generally 



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