BELL— ECHINODERMA. 21 



Notes on new or rare Species. 



Stereocidaris indica. 



Stereocidaris indica, Doderlein, Zool. Anz. xxiii. (1901) p. 19; id. Wiss. Ergebn. dent. Tiefsee 

 Exped. V. 2 (1906), p. 104; H. Lyrnaa Clark, Bull. Mus. Comp. Zool. li. no. 7 (1907), 

 p. 218. 



Prof. Doderlein has pointed out the variations exhibited by this species ; the specimens 

 collected by Mr. Gardiner appear to vary more in the length of the primary sjDines than 

 in any other particular ; some of these spines are completely covered by what is, 

 apparently, one species of Cirripede ; worm-tubes and Ophiurids may also find a home 

 on the spines, w hich, on the other hand, are at times singularly free of any Epizoa. 



I have adopted the name given by Doderlein and accepted by Prof. Lyman Clark, 

 though it " is the most poorly defined and unsatisfactory genus in the family," on the 

 ground that where one has not made, like DSderlein, " twenty years* study of the family " 

 {('f. Lyman Clark, op. cit. p. 170), or, like Prof. Clark, a profound study of the group in 

 question, it is unreasonable not to make use of the services such students have rendered 

 us. Personally, I greatly regret the dismemberment of genera which is now going on ; 

 a general survey of systematic zoology will come to be quite impossible if large genei-a, 

 such as Peripalus, Antedon, and Cidaris, continue to be broken up by specialists, while 

 the works of the founders, of our science will have to be re-edited and annotated. 



Saya de Malha, 150 fms. 



LYS ASTER, gen. nov. 



This new genus is a Pentagonasterid, having some of the characters of Iconaster, in 

 that the supero-marginals alone form the upper part of the area, but the abactinal plates 

 are so loosely connected with one another that they do not form a continuous roof, and 

 this surface is soft to the touch. The interradial plates on the actinal surface bear a 

 number of short sharp spines. The sides of tlie disc and arms are very deep, and the 

 granulation on the marginals is so regular that the median suture is often obscured. 

 This granulation is coarser on the sides of the marginals of the disc tlian in the median 

 part, so that each plate has the appearance of being sharply separated from its neighbour ; 

 this difference in granulation is not seen in the marginals of the arms. 



As there are but two specimens, and these almost exactly alike, it is difficult to be sure 

 as to the specific characters, but they appear to be as follows : — 



Lysaster lorioli, sp. nov. (Plate 3.) 



E,=2 r; about ten marginals in each half of a ray; here and there a more or less 

 sharp spine on the supero-marginals of the arm ; the madreporite quite close to the 

 supero-marginals. The ambulacral groove is bounded by a single row of moderately 

 developed spines, beyond whicli is a row of smaller and less numerous spines. 



Colour in alcohol : the margins and lower surface white, the sides of the marginals of 

 the disc and the central abactinal area somewhat darker, 



K,=57"5 ; 55-5. Depth at angle of disc 10 mm. 



Mauritius, 500-600 fms. 



