3-40 Annals of the South African Museum. 



OPHIOTHRIX LONGIPEDA. 



Ophiura lonyipeda Lamarck, 1816. Anim. s. Vert., vol. 2, p. 544. 

 Oph-iothrix longipeda Miiller and Troschel, 184*2. Syst. Ast., p. 113. 



It is rather odd that this big, common and long known species 

 has never been properly figured. The colored figure by Herklots 

 (1869, Ech. p. d'apres Nature, pi. 7) is unlike any specimen I have 

 ever seen, and I have examined scores of living individuals as well 

 as large numbers of museum specimens. 



The collection from the South African Museum extends the known 

 range of this tropical species far to the southward. This collection 

 contains six fragmentary specimens, of which the two larger ('20-22 

 mm.) are unquestionably longipeda, while the four smaller (6-13 mm.) 

 seem to be identical and are, with little doubt, the young. Their 

 only peculiarities are the lack of blue in the coloration and the 

 relatively short arms, which were apparently less than ten times 

 the disk diameter. They are poorly preserved however and all the 

 arms are more or less broken. There is reason to believe they 

 were much more brightly coloured in life. It is probable too that 

 in this species the relative length of the arms increases with age 

 until maturity. The largest specimen I have measured, alive, was 

 37 mm. across the disk and had arms 625 mm. long, or 17 times 

 the disk diameter. 



P.F. 12359. Umklangakulu River, N.W. by W., 7 miles, 50 fms. 

 S. and sh. 1 specimen; small adult. 



P.F. 12405. Itongazi River, N.W., 3 / 4 W., 3 miles, 25 fms. R. 

 and st. 4 specimens; adult and young. 



Delagoa Bay, P.E.A. K. H. Barnard, Oct. 1912. 1 specimen. 



* OPHIOTHRIX CAPENSIS. 

 Liitken, 1869. Add. ad Hist. Oph., pt. 3, pp. 59 and 100. 



This species does not seem to have been met with since its 

 original description, based on a specimen from the Cape of Good 

 Hope. It has never been figured but is apparently nearly related 

 to 0. suensonii of the West Indies. The concealment of the arm- 

 plates in skin is a very remarkable character in this species and 

 the radiating black lines on the disk would also seem to be 

 distinctive. 



