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Lytechinus pictus (Verrill). 



On a little dredging trip to San Diego the 7th September 1915 I secured 

 a few ripe specimens of this species; fertilization was made on board, 

 and the culture carried to La JoUa. It proved to be very good; the larvse 

 developed normally until the first stage, but then came a standstill in 

 their development, and as 1 had to leave La JoUa soon after, there was 

 no possibility of starting a new culture. — 



The larva was in all respects so closely like that of L. anamesus, 

 that there was no reason for giving a special description or figures of 

 it. — Perhaps the body rod is a little more branched and the recurrent 

 rod slightly smaller than in anamesus, but the difference is in any case 

 very unimportant — if at all constant. 



Also the fully formed larva can be stated to be closely like that of 

 anamesus. On the said dredging trip in San Diego Bay I found in a plankton 

 sample an Echinoid-larva, fully developed, which had the same characters 

 in shape and skeletal structure as the L. anamesus-lavva.. Since at that 

 time no other Echini than the two above named Lytechinus species had 

 ripe sexual products, it is beyond question that this larva also was a 

 Lytechinus larva, and the probability is, of course, that it belonged to 

 the species occurring at that place. 



Otherwise I wish to express here my doubt of the distinctness of these 

 two "species". 1 do not see that there is any reliable difference between 

 them; the typical forms, I agree, look very different; but there are all 

 transitions between them. In my opinion L. pictus and anamesus are 

 only the shallow water form and the deep water form or variety of one 

 and the same species. The close agreement of their larvae is in conformity 

 with this view, though in itself no proof of its correctness. 



Lytechinus panamensis Mrtsn.^) 



PI. VII Fig. 4. 



Of this, hitherto unknown, species which I discovered at Panama, 

 specimens containing ripe sexual products were found in December 1915 

 and fertilization was made with very good result. The early developmental 

 stages, which do not present any unusual features, pass very rapidly, 

 so that at the age of only 24 hours the embryo begins already to assume 

 the pluteus shape. The larva in its first stage (PL Vll Fig. 4) agrees very 

 closely with that of Lytech. variegatus and anamesus. The body is short 



1) This new species is distinguished from the other Lytechinus-species of the West Coast 

 of America in having the test uniformly reddish-brown coloured and the short spines some- 

 what* banded, redbrown and white. Ocular 1 is generally insert. It is a quite small form, 

 rarely exceeding 20 mm li. d., most specimens being only ca. 10 mm h. d. , 



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