ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 383 



desmus ; the presence of the l)olt-Hke pessnlus, with its ventral and 

 dorsal triangular plates ; the verv vestigial condition of the last five 

 tracheal rings, the greater development of the first two bronchial 

 semi-rings, and the close relationship of all these elements with the 

 ventral and dorsal plates ; the very noticeal)le absence of muscles in 

 direct or intimate association with the syringeal membranes ; and the 

 complex and intimate relationship of respiratory air-sacs to the syrinx as 

 a whole. 



Studies on the Mammalian Epiphysis Cerebri.* — H. E. Jordan 

 ogives a useful summarv of recent researches. Histolosrical studies 

 suggest that the pineal body has little functional value, limited to late 

 foetal or early post-natal (pre-pul)ertal) life, and this view is confirmed 

 by clinical and experimental observations. The practical absence of a 

 pineal body in the opossum (Jordan, 1911) adds further support to this 

 conclusion. Biedl, however, arrives at the conclusion that the pineal 

 body is an organ of internal secretion, with metabolic significance 

 limited to the young. The clinical symptoms associated with pineal 

 tumour may be due to pressure on the corpora quadrigemina, or, in- 

 directly, to disturbance of the pituitary body. There is some dis- 

 agreement as to histological details, some investigators finding evidence 

 of secretory cells, while others find none ; and this probably finds its 

 explanation in the fact that the pineal body, in common with rudimen- 

 tary organs generally, is the seat of regressive changes, and of some 

 degree of teratomatous alteration. 



Tunicata. 



Diazona violacea.t — W. A. Herdman shows that in the minute 

 structure of the branchial-sac the colonies of this beautiful Tunicate 

 from the Hebrides agree with those from the Mediterranean, though 

 there is a wide range- variation in the number of stigmata to a mesh, 

 and in the exact condition of the longitudinal bars. He calls attention 

 to the curious point that, whereas British specimens are green when 

 alive and become violet when preserved in spirit, Mediterranean speci- 

 mens are apparently sometimes violet and sometimes green, and the 

 latter do not always chano-e their colour when treated with alcohol. 



INVERTEBRATA. 



Mollusca. 

 n. Cephalopoda. 



Vascular System of Octopods.J — G. Grimpe gives a very careful 

 account of the vascular system of Octopods, with especial reference to 

 Eledone mosckata. He has been able to correct a number of errors and 

 to supply a connected account of the finer details of the vascular system. 



* Trans. Amer. Micr. Sec. xxxi. (1912) pp. 231-42. 



t Journ. Linn. See. (Zool.), xxxii. (1913) pp. 163-71 (2 pis. and 2 f^gs.). 



X Zeitschr. wiss. Zool., civ. (1913) pp. 531-621 ;3 pis. and 14 figs.). 



