55 



trace of a posterior transverse rod was seen; the dorsal arch had been 

 formed. The postero-dorsal rods are fenestrated as the postoral ones. 



In the second culture many of Ihe larvae were more or less abnormal, 

 the body skeleton forming a more or less developed meshwork. 



Mespilia globulus (Linn.). 



PI. VII, Figs. 1—2. 

 Th. Mortensen. On tlie flcvelopiiU'iil of sonic .Japanese Echinoderms. p. .546. 



Although this species^) is fairly common in shallow water near the 

 Biological Station at Misaki, it was quite difficult to get a culture of it, 

 partly because its breeding season appears to be somewhat later in the 

 summer, partly because it was found to be very generally infested with 

 a Trematod living in its genital organs and destroying these more or less 

 completely. I succeeded, however, in getting a fertilization of it on .Tune 

 25th 1914, which 

 gave a small, but 

 sufficient number of 

 larvae. They devel- 

 oped quite normally 

 until beginning me- 

 tamorphosis, when 

 the surviving spec- 

 imens had to be pre- 

 served on my depart 

 from the station. 



The developmen- 

 tal processes do not 

 go on so fast as in 

 TemiwpU'urus loreu- 

 mnticiis; the embry- 

 os had not yet pas- 

 sed the blastula stage at the age of ca. 24 hours. The young Pluteus 

 does not alYord any very marked features; the body is not quite so 

 elongate as in the two other Temnopleurid-larva^ described above, ami 

 the stomach is not quite so small as in these. Pigmentation is very scarce. 



') Voshiwara (Preliminary Notice ol new .lapanese Eehinoids. Annol. Zool. .laponenses. 

 II. 1898, p. 58) has establislied tlie species M. leviluherculata for the Japanese form of Mfspilia. 

 H. L. Clark (Hawaiian and other Pacific Echini. The Pedinida: .... Echinida-. Temno- 

 pleuridiB .... .Mem. Mus. Comp. Zool. XX.XIV. No. 4. 1912. p. ;V22) maintains that it cannot 

 be separated from the typical M. ulobiiliis (L.). On adopting the name M. ghhuliis for it 

 here I must state that it is on the authority of H. L. Clark, having not yet had the opport- 

 unity of critically examining the (|uestion myself. 



Fig. 18. Skeleton of larva of Mespilia globulus, 1st stage. 

 .\. front view: B. side view. ■'"»/,. In fig. H. the postoral rod 

 is ahnormally widened into a fenestrated plate: also in fig. -A 

 Mure is a slight abnormity at Ihe base of the right postoral 

 rod. Letters as in tig. o. 



