Bodi/ Sjhtncfi of 11)1(1 (jiiadr'iVidnis. 'Z21 



promineuL-e (Plate VI., Fig. 1, t.p.) projectino: at right angles to 

 the mouth parts. In section each prouiinence is see<n to contain 

 a duct which serves for communication between the exterior 

 and a large internal space. (Plate VI., Figs. 2, 3 and 5, A.) 

 The two spaces, one on either side of the body, are most notice- 

 able in sections, being symmetrical, and, in marked contrast to 

 the ordinary irregular body spaces in the animal being lined 

 throughout by a definite layer of flattened epithelium. They are 

 situated ventral to the oesophagus, and are quite separate, only 

 approaching one another at one place. Though Gruvel says that 

 in Balanus tintmnahuluyn there is a connection between them 

 at this point [Gruvel, 5], I have been quite unable to detect any 

 in Ibla after careful examination of continuous series of sections 

 of several specimens. If the spaces (A) are traced through such 

 a series, each of them is found to open towards its own side of the 

 body into another large cavity (Plate VI., Fig. 5, C), the outer 

 part of which is in contact \yth'the body wall, and which is 

 evidently the equivaleoit of the nephroperitoneal sac present in 

 certain Decapods, e.g., Palaemon and Pandalus [Weldon, 17]. 

 Into the large cavity (C. A.) opens on each side a space (Plate VI., 

 Figs. 2, 3, 4 and 5, B.), lined by somewhat irregular cubical- 

 shaped granular cells. They are apparently heaped upon the 

 walls, and in addition form irregular partitions running across 

 the cavity. Where this space opens into the large cavity 

 (C. A.), these granular cells and their partitions disappear and the 

 cavity is lined by pavement epithelial cells (Fig. 4, y.) resem- 

 bling those of the portion into which the duct first opens. 



We see then, that each of the organs in question consists of a 

 glandular part (B), opening into a large saooular bladder (C. A. ), 

 which oommimicates with the exterior by a duct opening at the 

 base of the second maxilla (Plate VI., Fig. 5). 



The tube which opens to the exterior, is lined near to the 

 external opening by a single layer of cells with their nuclei 

 parallel to the length of the lumen. After some distance the 

 character of the lining of the duct changes, the cells becoming 

 cubic, and finally almost columnai' in shape, though there is still 

 only a single row present. The nuclei are arranged very dis- 

 tinctly with their greatest length at right angles t(j the lumen 

 of the duct. As the tube recedes from the surface it becomes 



slightly wider, and in one of my series is distinctly funnel- 



16a • 



