Note on a Gigantic Form of Auricularia 

 Allied to A. 1:11 dibranchi aia Chun. 



By 



Hiroslii Ohshima, Rigakushi. 



Zool. Inst., Tokyo Imp. Univ. 



The remarkable Holothurian larva, Auricularia mtdibranchictta, 

 was first discovered at Orotava, Canary Islands, in 1887 and was 

 carefully studied by CHUN.* No second record of the discovery of 

 the same or a similar larva seems to have since been given from 

 an)' part of the world. In the Misaki Marine Station, there came 

 into observation from time to time since 1898, a gigantic form of 

 Auricularia which is apparenti)' very closely allied to, if not 

 identical with, the Orotavan form described by CHUN. As recorded 

 in the diary of the Station, the first specimen of the larva was 

 obtained on December 29th. of that year, followed by two specimens 

 on the following da)-; and on Januar)- 2nd., 1S99, thirty six more 

 individuals seem to have been collected. During the winter of 1910, 

 I myself have had the good fortune of capturing a few specimens, 

 besides coming into possession of some more which were taken by 

 Messrs. K. AOKI and S. FUJITA of the Station and have been preserved 

 in formalin. Now, here will be given a short account of my obser- 

 vations on the larva in both living and preserved states. 



At the outset it may be mentioned that in all essential points 

 of external and internal organization, the Misaki form shows close 

 agreement with that of Orotava. As in the latter case, nothing 

 whatever is known as to the metamorphosis or the adult condition 

 of the larva. 



* Atlantis. Biologische Studien über pelagische Organismen, II. Auricularia nudi- 

 traHchiata. Eibl. Zool., Heft 19, iSç 1 ;. 



