42 Memoirs of the Indian Museum. [Vol. Ill, 



contains five or six of the large darkly-staining granules which are almost certainly 

 cement-substance. The protoplasm is finely granular, and contains in many cases 

 small rounded vesicular nuclei, each containing a single chromatin granule. These 

 minute nuclei appear to be identical with the wandering nuclei of the ova, and are 

 doubtless supplying nourishment to the cement cells. 



The glands in the fully grown specimens (compare Hoek, 8, p. 30) consist of these 

 large cells scattered separately throughout the upper half of the peduncle, often lying 

 among the ovarian tubes, but never in any way connected with these. Each cell is 

 enclosed in a capsule of fibrous tissue, which is perforated at one point by the duc- 

 tule {d.). This ductule, still retaining its fine nucleated wall, enters the body of the 

 cement cell, approaches the nucleus, and branches freely around this latter structure 

 {dl.) After leaving the capsule of the cell, neighbouring ductules unite together, and 

 the ducts so formed enter certain curious little spherical bodies composed of fibrous 

 tissue. Here the ducts are thrown into convolutions, the convolutions being bound 

 together by the fibrous tissue of the nodules. On leaving the nodules they acquire 

 an internal lining of cuticle. They unite with each other until finally only two main 

 ducts are left. 



The nodules are the bodies which Darwin regarded as the cement glands. 



It appears then that, in the younger stages, many of the cement cells contain a 

 considerable quantity of yolk from which the cement may be manufactured, and that 

 in the older forms the nucleus is the portion of the gland cell which produces this 

 secretion. 



(6) Development of the ovaries.^ — The youngest specimens in which it is possible 

 to recognize the ovaries are adults measuring 25 mm. in length (pi. vi, fig. 2). In 

 these two small aggregations of nuclei can be found embedded one on either side in 

 the wall of the rostral duct in the uppermost portion of the peduncle {ov.). 



The nuclei, of which not more than three appear in a section, lie in a thin 

 cylindrical protoplasmic mass, measuring approximately -3 mm. in length. This 

 syncytium is surrounded by a délicate membrane continuous with the connective 

 tissue of the wall of the rostral duct. The nuclei are minute ("005 mm. in diameter), 

 generally oval, with a delicate nuclear membrane, very fine chromatin granules and 

 a minute nucleolus. They cannot be distinguished from the ordinary connective 

 tissue nuclei, except by their position and grouping together. There is no trace of a 

 duct leading to the prosoma, and to attain the adult functional state the glands must 

 grow both upward and downward. 



In the pupa (pi. vi, fig. i) at the corresponding points there are more nuclei 

 than in other portions of the rostral duct. They are not, however, shut off, and, 

 although some of them are doubtless the developing ovarian nuclei, it is not possible 

 to say which are. They are generally about the same size as the ovarian nuclei in 

 2-5 mm. specimens. There is some likelihood from the appearances found in these 

 sections that the two ovarian cylinders arise from the epithehum lining the rostral duct 



I Compare Hoek, 8, p. 7, and pi. ii, figs, i and 2. 



