464 DISCOVERY REPORTS 



muscle running straight from one point of attachment to the other. Now, in one of 

 my preparations, which is exceptionally well fixed, certain of the longitudinal strands 

 forni loops which follow the bulges of the gut epithelial cells into the parenchyma. 

 However, certain of the longitudinal strands can be traced forwards down the oeso- 

 phagus and backwards to the anus, and in these regions they stain a purplish red and 

 exhibit a typical striation. Certain of the transverse strands in the proctodaeal region 

 appear as slings for the gut. In the median region they support the gut epithelium 

 and are homogeneous. Laterally, they leave the gut musculature and attach to the body 

 wall, and in so doing exhibit a complete striation. I could find no nuclei in association 

 with the muscle strands. 



I know of no similar musculature in any other Crustacean, but in the young larva 

 of Estherio, before any true gut musculature was formed, I described (1924, p. 399) 

 long, homogeneous strands extending forwards over the surface of the gut from the 

 proctodaeal musculature. 



Liiders (1909, p. 113), in his description of Gigantocypris agassizii, describes a muscle 

 layer in a similar position, but does not mention the chequer arrangement of the muscles 

 or comment on any peculiarity of the individual strands. It is stated by Liiders (1909, 

 p. 113) that, according to Miiller, Gigantocypris pellucida diff"ers from Gigantocypris 

 agassizii in lacking this muscle layer. It may be that the homogeneity of the muscles 

 rendered them non-staining in the technique he employed. The staining reaction in 

 my material diff'ered markedly in different specimens. In the best the staining was 

 intense, but in others not so well fixed, the musculature stained a pale orange and was 

 difficult to distinguish. 



The gut parenchyma is composed of three zones, an inner epithelium, a middle mass 

 and an outer layer. 



The inner epithelium consists of a layer of very large cells covering the gut muscula- 

 ture (Fig. 8). As already described the bases of these cells interdigitate with the bases 

 of the gut epithelial cells. The actual position of the gut musculature in relation to these 

 two epithelia is uncertain. It probably lies in between the two, but, in sections, it 

 appears as if the muscle strands actually pass through the cytoplasm of the cells of 

 one or other of the epithelia. 



The middle mass contains two distinct types of cell. The first, a large cell enormously 

 distended with coagulable matter. These I call reserve cells and they form the main bulk 

 of the parenchyma. Their nuclei are very much flattened, presumably owing to the 

 distension of the cell body, and stain intensely. The second can only be identified from 

 their nuclei, which have well-defined nucleoli and do not stain intensely. These, I 

 believe, form the walls of a system of ramifying lacunae and canaliculi which lie in 

 the interstices between the reserve cells. It is into this system that the blood is passed 

 from the heart through the hepatic valves. 



The outer layer of cells forms an epithelium covering the whole of the gut paren- 

 chyma. The cells are for the most part flattened, but in places the layer dips down 

 into a crypt (Fig. 8) and the cells become more polyhedral. Also posteriorly there is 



