260 SUMMARY OF CURRENT RESEARCHES RELATING TO 



short body with a complicated body-skeleton forming a peculiar frame. 

 In the later stages of S. pulcherrimux the long body-rods are absorbed 

 and the body shortened. 



The larva of Toxocidaris tuberculatum is quite different in shape and 

 skeleton from 8. pulcherrimus. In the first stage it is like 2'oxopneustes 

 pilosus ; the body is short and the skeleton of the body forms a frame, 

 the rods being very thorny. In a later stage a posterior cross rod is 

 developed, ending in two very peculiar postero-lateral antler-like rods. 

 Mortensen's reference of Toxocidaris to the Echinometridae has not yet 

 received any confirmation from his study of the larvae. 



The larvae of three Temnopleuridae agreed in body-skeleton. 80 did 

 four Olypeastroids. The case of one of these, Laganum fudsiyama (or per- 

 haps pellucidum), is particularly interesting, for it is the first Echinoderm 

 from the deeper waters (200 to 800 metres) whose development has been 

 studied. It has quite typically pelagic larvae of the common Clypeastroid 

 shape. While believing that deep-sea Echinoderms in general have no 

 pelagic larvae, but undergo more or less direct development, Mortensen 

 thinks that there are some — perhaps only among archibenthal forms, and 

 not among those from very deep waters — that have pelagic larvae. He 

 suggests that in the case of a small species Orechinus from the Sagami Sea 

 and in Salenia pacifica there will be pelagic larvae as in the species of 

 Laganum already noted. In L. decagonale the eggs are large, 0*5 mm. 

 in diameter, and with yolk ; the development is shortened— the whole 

 metamorphosis being accomplished in three or four days. The larva? 

 are pelagic, reduced, and very variable in shape. They may show four, 

 three, or two processes, or only one, or none ; but the metamorphosis 

 goes on just the same whatever be the number. There is a general 

 ciliation of the whole body ; the intestine is rudimentary and without 

 an anus ; the mouth is very small and the larva does not seem to feed. 



In Asterina pectinifera the eggs are small and the larvae pelagic, a 

 contrast to A. gibbosa, which has large eggs and pelagic larva?. The 

 larva of A. pectinifera has a Brachiolaria stage. In Aster ias calamaria 

 there is autotomy in the younger stages. Nearly all the larger specimens 

 opened contained genital organs with large, white, biserially arranged 

 oval eggs, but these turned out to be the eggs of a parasite, probably a 

 Cirripede. 



Tetramerous Sea-Urchin.* — A. Robert calls attention to a specimen 

 of Sphserechinus granulans, which showed a thorough-going tetramerous 

 symmetry. No details are given. 



Indian Ocean Spatangidse.t — Rene Koehler gives an account of the 

 Spatangidaj in the collection of the Indian Museum, including new 

 species of Pourtalesia, Aceste, Lovenia, Prymnaster, etc. Out of the 

 thirty-one species described, thirty-one are new, and we refer to the 

 memoir especially because of its detailed description and fine illustration 

 of the minute pedicellaria?. 



* Bull. Soc. Zool. Prance, xxxix. (1915) p. 353. 



t Echinoderma of Indian Museum, pt. viii. (1914) pp. 1-258 (20 pis.). 



