ECHINOIDEA. II. 



131 



be referred to .S'. Raschi\ but the other characters (especiall\- the subanal fasciole and the pedicellariæ) 

 are qnite those of purpureus. The petals are somewhat shorter than usual, especially the posterior 

 ones. The nieasurenients of this specimen are: Length: 54""°, height: 34""", length of posterior petals: 

 j5tnm Those of an eqnal-sized specimen of pzirpureus are: Length: éo""", height: 29""", length of 

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

 S. Ras c hi. 



I mav here take the occasion to give some remarks on Spat. Lutke?ii A. Ag., based on the type 

 specimen of Spat. altus Liitken (M. S.), which is stated by Agassiz ('<Revision of Echini-v p. 158) to 

 be a synonym of 5. Liitkeni. There are, however, some points in the description given by Agassiz 

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

 whether it is really identical with 6". Liitkeni. Unfortnnately Agassiz has given no figures of the 

 species. Recently Profes.sor Doderlein (Echinoiden d. deutsch. Tiefsee-Exp.) has given some fignres 

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

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

 5". alt2t,s Ltk., leaving it to somebody who has access to the true 5". Liitkeni 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 S. Liitkeni, it will have to keep 

 the name 6". altus Ltk. 



This species shows a remarkable union of features characteristic of both 6". p2irpureus and 

 Rasclii, much in the same wa}' as 6". capensis. The test |P1. 1. Figs. i— 3) is high as in .S". Raschi, but 

 the tuberculation is more like that of purpuretis, no jjrimary tubercles occurring in the ambulacra on 

 the abactinal side. In the paired abactinal interambulacra the primårs- 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 closely agreeing with the 

 arrangement in 5. capensis. In the description of 51 Liitkeni Agassiz says (p. 565): cthe 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 tlian in 

 6"". Rasclii; the test is rather sunken towards the actinostome as in Rasclii. but the labrum is short 

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

 Raschi; three pairs of pores (four ambulacral piates) are enclosed within the fasciole, a character most 

 decidedly distinguishing this species from purptireus, Raschi and capensis^., in which only two pairs 

 of pores (three ambulacral piates) are included by the fasciole. The petals are decidedh- broader than 

 in purpureus and Raschi, whereas 5". capensis 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 speciniens of this species ex- 

 amined by me in the British Museum I find in the »Challengers-specimeu only one pair of pores enclosed in the subanal 

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



17* 



