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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; ferlili/alion was made on board, 

 and the culture carried to La Jolla. It proved to be very good; the larva 1 

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

 their development, and as I had to leave La Jolla soon after, then.- was 

 no possibility of starling a new culture. - 



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

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

 il. - Perhaps the body rod is a little more branched and the recurrent 

 rod slightly smaller Hum in unninesus, but Ihe dilTerence is in any case 

 very unimportant if al all constant. 



Also the fully formed larva can be staled to IK- closely like that of 

 (tiutmesus. On the said dredging trip in San Diego Hay 1 found in a plankton 

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

 in shape and skeletal structure as the L. untuni'sus-larva. Since at that 

 time no other Kchini than the two above named Lylechinus species had 

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

 Lylechinus larva, and the probability is, of course, that il belonged to 

 the species occurring at that place. 



Otherwise I wish to express here my doubt of the 1 distinctness of these 

 two "species". I do not see that there is any reliable di (Terence between 

 them; the typical forms, 1 agree, look very did'erenl; but there arc all 

 transitions between them. In my opinion L. />/V/.v and diutmcxufi are 

 only the shallow water form and the dee]) water form or variety of one 

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

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



Lytechinus panamensis Mitsn.'i 



II. VII Fig. I. 



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 21 hours the embryo begins already to assume 

 the pluleus shape. The larva in its lirsl stage (PI. .VI I Fig. 1) agrees very 

 closely with that of Lylccli. itric</<tlux and nnniin'siis. The body is short 



') This new species is distinguished from I he oilier /.;//<r/i/m/.x species of I lie \\esl Coasl 

 of America in having Ihr lesl uniformly reddish-brown coloured and Ihe short spines some- 

 what handed, redbrowu and white. Ocular I is generally insert. II is a quite small form, 

 rarely exceeding 20 mm h. d.. mnsl specimens being only ca. Id mm h. d. 



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