ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 803 



opened at such a time the conversion of the glandular cells into a 

 blood-corpuscle may be seen to be effected very rapidly. In Asterina 

 gibbosa the gland is divided into three lobes. 



Regeneration of Visceral Mass in Antedon rosaceus.* — Mr. A. 

 Dendy carries further the observations commenced by Prof. Milnes 

 Marshall on the regeneration of the visceral mass in the common Eosy 

 Feather-star. There are differences in the resistance which the mass 

 offers to evisceration, and it was observed that the mass was more 

 firmly attached to the calyx in those specimens in which the pinnules 

 were found to be much distended with genital products. It is possible 

 that these facts are to be correlated, the energies of the animal not 

 allowing of reproduction simultaneously with the reparation of such an 

 amount of tissue as is represented by the visceral mass. 



Eegeneration appears to commence by a series of outgrowths from 

 the thin layer of connective tissue which forms the floor of the visceral 

 basin, and by an ingrowth of connective tissue and epidermis from 

 the edges of the injured area. The latter forms a roof to the visceral 

 basin. It is not certain how the alimentary canal is formed, but the 

 author thinks it probable that it is effected by invagination. The 

 ambulacral grooves appear to be areas in which the regenerating tissue 

 is less thick than elsewhere. Thickening seems to take place cen- 

 tripetally. 



Mr. Dendy suggests that evisceration is a normal occurrence in 

 Antedon, and is due to the fact that if any irritating particles or 

 dangerous parasite be taken in as food the only way in which the 

 obnoxious matter could be got rid of would be by the casting out of 

 the alimentary canal. Owing to the structure and relations of this 

 part the process is best effected by rejecting the entire visceral mass. 



Variations in the form of Cirri in Comatulae.t — Dr. P. H. 

 Carpenter describes the cirri of Antedon pJialangium as being of four 

 different types, which he groups as long-jointed, intermediate, square- 

 jointed, and short-jointed. This variation is the more remarkable 

 since in most Crinoids the cirri are very constant in their characters. 



Comatulse of the Willem Barents Expedition. | — Dr. P. H. 

 Carpenter gives an account of the four Antedons collected by this 

 expedition. Of them A. barentsi is a new species, most remarkable 

 for the extensive development of the anambulacral plates in the peri- 

 some of the genital pinnules, wherein it resembles the Comatula? of 

 the Caribbean Sea and Oceania. 



Ccelenterata. 



New Form of Fresh-water Coelenterate.§ — In 1871 Owsjannikow || 

 described a peculiar parasite in the ova of Acipenser, and his report 



* Studies from the Biological Laboratories of the Owens College, i. (188G) 

 pp. 299-312. 



t Trans. Linn. Soc. Lond.— Zool., ii. (1886) pp. 475-80 (1 pi.). 



t Bijdragfcii tot de Dierkunde, xiii. (1886) pp. 1-12 (1 pi.). 



§ Morphol. Jahrb., xii. (1886) pp. 137-53 (2 pis.). 



|| Arbeit, dritten Russ. Naturf. Kiew. Reported in Zeitschr. f. Wiss. Zool., 

 xxii. p. 292. 



3 g 2 



