704 SUMMARY OF CURRENT RESEARCHES RELATING TO 



very large, and in every way similar to that of the Cyclostomata. The 

 ancestrula is the tubular superstructure of the primary individual. It 

 is a simple, undifferentiated, tubular zocecium. The earlier formed 

 zooecia (nepiastic zooecia) of the Fcnestella colony differ markedly in 

 shape and size from later formed (neanastic and ephebastic) zooecia. In 

 every feature in which they depart from the ephebastic zooecia of 

 Fenestella, they approach the ephebastic zooecia of Cyclostoinata. The 

 terminology of the paper is highly specialised. 



Echinoderma. 



Species of Holothuria.* — C. L. Edwards has applied biometrical 

 methods to the taxonomic question of the relations of Holothuria atra 

 Jager, H. fioridana Pourtales, and H. mexicana Ludwig. He has de- 

 termined the extent of variation, and thus the best (least variable) 

 specific characters. The two last-named species are synonymous, 

 H. fioridana surviving ; but H. atra is distinct. The author notes that 

 the number and length of polian vesicles and of stone-canals increase 

 with age ; 71 p.c. of the young H. fioridana have only one polian vesicle, 

 while in the adult the number ranges from 1 to 1)2. The total number 

 of stone-canals in H. fioridana ranges, in the young, from 2 to 25 ; in 

 the adult, from 5 to 149. 



Korean Holothurians.t — Hjalmar Ostergren describes Myriotrochus 

 mintttus sp. n., and Eupyrgus pacificus sp. n., two new Korean Holo- 

 thurians of minute size. 



Tentacle Reflex in Holothurians.J — Caswell Grave has studied the 

 contraction of the oral tentacles which takes place when Holothurians 

 {Cucumaria pidcherrima) are disturbed, and their invagination within 

 the body. It seems to be at first an instinctive action, but in the 

 absence of constant stimulation and use, in a quiet aquarium, it rapidly 

 loses its efficiency. In the abnormally safe and undisturbed conditions 

 of captivity the reflex seems almost to disappear. 



Note on Cucumaria Montagui Fleming.§ — A. M. Norman gives 

 convincing reasons for maintaining that Cucumaria normani sp. n., 

 recently established by Pace, must be cancelled, in favour of the older 

 G. montagui Flem. The question largely turns on the fact that 

 spicules which have six perforations are- apparently the young forms of 

 spicules in which the number of perforations is almost invariably four 

 and never six. 



Development of an Asterid with Large Yolked Eggs.|| — E. H. 

 Henderson describes the development of a starfish from the Franklin 

 Islands, which shows a close parallelism with the development of 

 Asterina gibbosa as described by MacBride. Noteworthy is the large 

 amount of yolk, which forms at least nine-tenths of the whole bulk of 

 the embryo. 



* Science, xxi. (1905) pp. 383-4. 



t Arch. Zool. Expe'r., iii. (1905) Notes et Revue, No. 8. pp. cxcii.-cxcix. (1 fig.). 



% Johns Hopkins Univ. Circular, No. 5 (1905) pp. 24-7. 



§ Ann. and Mag. Nat. Hist., No. 93 (1905) pp. 352-9 (1 pi.). 



|| Ann. Nat. Hist., xvi. (1905; pp. 387-92 (2 pis.). 



