ECHINOIDKA. II. 1,1 



be referred to S. J-iasc/ii\ but the other characters (especially the subanal fascicle and the pedicellarise) 

 are quite those of pnrpurcus. Tlie petals are somewhat shorter than usual, especially the posterior 

 ones. The measurements of this specimen are: Length: 54™"', height: 34""", length of posterior petals: 

 16'"™. Those of an equal-sized specimen of pnrpurcus are: Length: 60'"'", height: 29""", length of 

 posterior petals: 21™"'. I think it rather certain that we have here a hybrid of S. purpureus and 

 ^1 Rasclii. 



I may here take the occasion to give some remarks on Spat. Lutkcni A. Ag., based on the type 

 specimen of Spaf. alhis Liitken (M. S.), which is stated by A gas si z (« Revision of Echini > p. 158) to 

 be a synonym of X Liltkeni. There are, however, some points in the description given by Agassiz 

 in Revis. of Ech. p. 564, which do not suit with this specimen, so that it may perhaps be doubtful, 

 whether it is really identical with S. Lutkeiii. Unfortunately Agassiz has gi\-en no figures of the 

 species. Recently Professor Doderlein (Echinoiden d. deutsch. Tiefsee-Exp.) has given some figures 

 and descriptive remarks of S. Lutkeni — they do not agree with the present specimen either. I am 

 unable to decide the question and can only give a description and figures of the type specimen of 

 i^. nltus Ltk., leaving it to somebody who has access to the true X Lutkeni to decide, if they are 

 really identical; in that case the specimen figured by Doderlein will probably represent a new 

 species. In case the present specimen proves to be another species than X Lutkeni, it will have to keep 

 the name 6". alius Ltk. 



This species shows a remarkable union of features characteristic of both S. purpureus and 

 Rasclii, much in the same way as S. capcnsis. The test (PI. I. Figs, i — 3) is high as in .S". Raschi, but 

 the tuberculation is more like that of purpurctis. no primary tubercles occurring in the ambulacra on 

 the abactinal side. In the paired abactinal interambulacra the primary tubercles form a very distinct 

 transverse series on each plate except one or two at the ambitus, an arrangement which is not in 

 accordance with the descriptions of Agassiz and Doderlein, but rather closeh- agreeing with the 

 arrangement in 5". capcnsis. In the description of 5". Lutkeni Agassiz says (p. 565): «the small tub- 

 ercles covering the abactinal surface are much larger and more closely crowded than in the other 

 species-; perhaps ^larger is a lapsus calami for «smaller^ — in any case they are very small in the 

 present specimen, smaller than in the other species. The actinal plastron is somewhat broader than in 

 5. Rasc/ii; the test is rather sunken towards the actinostome as in Rasc/ii. but the labrum is sliort 

 and broad as in purpureus. The area enclosed by the subanal fasciole is not much larger than in 

 Rasc/ii; three pairs of pores (four ambulacral plates) are enclosed within the fasciole, a character most 

 decidedly distinguishing this species from purpureus. Rasc/ii and capcnsis^, in which only two jDairs 

 of pores (three ambulacral plates) are included by the fasciole. The petals are decidedly broader than 

 in piirpureus and Rasclii. whereas X capcnsis comes rather near to it also in this respect. According 

 to the description in Rev. of Ech.» the lateral petals are proportionally shorter than in the other 

 species, which does not hold good either of the present specimen. In the specimen figured by Doder- 

 lein the petals are much narrower than in the present specimen. 



■ Doderlein does not give any information of this feature in Sp. capensis; of the specimens of this species ex- 

 amined by me in the British Museum I find in the « Challenger >-specimen only one pair of pores enclosed in the subanal 

 area, iu the other specimen 2 pairs (or at least on one side 2 pores). 



17* 



