ANATOMY AND PHYSIOLOGY. 
Moll 31 
u indirect injection,” which, if it proved anything, would show that the 
foot is covered all over with pori. The experiment of placing mussels in 
water containing finely-divided colouring matter gave a negative result. 
The streams of water which issue from the foot when the Anodon is 
removed from the water arise from its bursting, owing to the blood con¬ 
tained in the organ being unable to escape by the normal channels. The 
author then proceeds to discuss mechanical difficulties in the way of the 
entrance of water through the supposed pores, either in a distended or 
contracted state of the foot, devoting some time to a discussion of Saba¬ 
tier’s statements regarding Mytilus edulis. Bivalves have not great need 
of oxygen. Injection has long since shown that the arteries were com¬ 
petent fully to distend the foot, if only there were sufficient blood in the 
body for the purpose. Fleischmann shows that about 50 per cent, of the 
weight of an Anodon is blood, which is quite sufficient for this purpose. 
When the foot is retracted the “ muscle-hood ” is comparatively thin, and 
its fibres closely packed, while the visceral cavity is widely distended ; on 
protrusion of the foot these conditions are reversed. The blood used 
in distending the foot is contained in the mantle, which holds about half 
the total quantity of blood in the body. “ Keber’s valve,” between the 
veins of the foot and of the kidney, is the means by which a congestion 
in the former organ is rendered possible, and details are also given as to 
the mode by which the circulation is carried on during its turgescence. 
Arguments are also adduced against the possibility of an influx of water 
through the organ of Bojanus and through the intercellular passages. 
G-riesbach (147) replies, upholding the existence of pori aquiferi. See 
also a remark by Carriere, Arch. mikr. Anat. xxiv. p. 37, footnote. 
A discussion of this question, with arguments based mainly upon injec^ 
tions and subsequent cutting into series of sections, is given by Koll- 
mann (214). 
Botjrne (42) denies the existence of the communication between the 
vascular system and exterior said by Lacaze-Duthiers to exist in Pleuro- 
branchus. 
5 . Respiratory System. 
Respiration of Pulmonata in deep water discussed by Forel, (133) 
p. 196. 
Vayssiere (365) describes in great detail the anatomy of Truncatella 
truncatula , especially the respiratory apparatus, which is shown to consist 
of a gill placed transversely in a respiratory cavity. 
Joubin (203) traces the development of the branchia in Sepia from an 
elongated papilla, not ciliated like the mantle-cavity, which becomes 
divided by transverse grooves into a number of laminae, each of which 
becomes folded in its turn, an afferent vessel passing to the elevated and 
depressed portions of each fold. The vessels arise in the midst of masses 
of cells, and have proper membranous walls ; they are connected by inter¬ 
cellular lacunar spaces. The branchial gland is formed along the internal 
margin of the gill from cells which have not taken part in the formation 
of the lamellae, but which form a spongy tissue. Muscular fibres pass 
