ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 47 



tion of the epithelium after a wound the adjacent ceils spread over the 

 wound till they meet in the middle. A thin epithelium with few nuclei 

 is formed and parenchyma cells wander into it, insinuating themselves 

 among the elongated old cells. Both sets of cells multiply amitotically 

 and a normal epithelium is retored. But its cells cannot multiply mito- 

 tically. The structure and the regeneration of the pharynx are discussed. 

 Besides the main eyes there are accessory eyes (one or two) in about 

 ;">0 p.c. of cases. They lie in front of the main eyes, nearer the middle 

 line. They are smaller than the main eyes, but may show the same 

 structure, though with small pigment-cup and fewer visual cells. Not 

 to be confused with accessory eyes are abnormal or supernumerary eyes 

 of inconstant form, position, and structure. 



Echinoderma. 



Development of some Echinoderms.*— Th. Mortensen describes 

 the bipinnaria of Asterias glacialis (in which two dorsal pores were 

 present in about 50 p.c. of cases) ; the bipinnaria of Luidia ciliaris (the 

 grown female has no fewer than 200 millions of eggs) ; the ophiopluteus 

 of Ophiactis balli (in which recurrent rods are present in the skeleton so 

 that two large meshes are formed in each half of the body) ; the larva of 

 Ophiocoma nigra ; the echinopluteus of Spatangus purpureus, which is 

 3 ' 5 mm. in length with long processes — all except the pre-oral with a 

 conspicuous red point ; and the larva of Holothuria nigra, which is a 

 typical Auricularia with a star-shaped spicule at the posterior end. 



Ova of Echinaster sepositus.f — F. Rosen describes the ovum of 

 this starfish, which is unusually rich in yolk. At the beginning of the 

 ovum's growth there is one nucleolus ; it grows greatly and falls into 

 hundreds of small nucleoli. Some of the nucleolar forms are deceptively 

 like tetrads, but there are quite distinct chromosomes and tetrads. 

 The chromosomes retain their continuity on to the maturation division, 

 and are quite independent of the nucleolar apparatus. 



Development of Sea-urchins.:}: — L. v. Ubisch has studied Strongylo- 

 centrotus lividus, Echinus microtuberculatus, and Arbacia pustidosa, 

 and confirms in the main the accounts of the development given by 

 MacBride and Theel. He describes the primordia of the chief organs 

 and the differentiation of the water-vasculiir system, the epineural 

 canals, the nervous system, the skeleton, Aristotle's lantern, the gut, 

 the ccelom, and so on. Some abnormal duplex larva? are described. 



Ccelentera. 



Study of Eleutheria.§— Anna Drzewina and G. Bohn have studied 

 the polyps and medusoids of Ehutheria dichotoma and E. claparedii. 

 They fed them on minute supra-littoral Copepods, which are stung by 

 the ends of the arms. A detached end may go on for several days 



* Journ. Marine Biol. Assoc, x. (1913) pp. 1-18 (15 figs.), 

 t Anat. Anzeig., xliv. (1913) pp. 381-3 (4 figs.). 

 X Zeitschr. wiss. Zool., c. (1913) pp. 409-48 (3 pis. and 20 figs.). 

 § Arch. Zool. Exper., liii. (1913) pp. 15-60 (37 figs.). 



