REPORT ON THE CIRRIPEDIA. 41 



the centre of the egg, and in the second place, rounded groups of very small ovigerms, 

 forming together what the Germans call the "Keimlager." One or two of these ovi- 

 germs are often slightly larger than the rest, and these will be the first to develop into 

 ovarian eggs after those which are already mature are evacuated. 



In a ripe or nearly ripe ovarian egg of Scalpettum vulgare which had a diameter of 

 0*3 mm., a nucleus of 0"036 mm was present, having a nucleolus of - 009 mm. The 

 nuclei of the cells placed along the wall of the ovary are oval and measure about 

 0*01 by - 005 mm.; the small ovigerms are nearly circular and have a diameter of 

 about 0'013 mm. Their nuclei, of course, are a great deal smaller than those of the ripe 

 ovarian eggs. One of the ovigerms was considerably larger ; it was rounded oval, its 

 diameters being 0'03 and 0'023 mm.; its nucleus was about 0'0i2 mm. A ripe ovarian egg 

 of Scalpettum vulgare is filled with a coarsely granulated vitelline mass (PI. VI. figs. I A, 

 2x). Between the larger granules, which in the microscopical preparations appear like 

 vesicles, a much more delicately granulated mass of plasma is here and there visible ; 

 sometimes a layer of this is placed in the centre round the nucleus. The wall of 

 the ovarian egg seems to be a very thin and structureless membrane, and neither 

 in the case of Scalpettum, nor of any of the other genera observed, was a follicular 

 epithelium present. The mature ovarian eggs of Scalpettum regium are about 

 0"6 mm. in diameter. They are very coarsely granulated; they do not quite fill 

 the interior of the ovarian cceca, but between them, and also between each egg and 

 the wall of the ccecum, a layer of a much more delicately granulated mass of plasma is 

 visible (PI. VI. fig. 3). Here the ovigerms form groups of little cells, the dimen- 

 sions of which nearly correspond to those of Scalpettum vulgare. In one of these groups 

 I counted about 20 of these ovigerms. Here again one of these ovigerms was developed 

 into a young ovarian egg. The wall of the cceca shows the same cellular elements as in 

 Scalpettum vulgare ; its outer surface is formed by a distinct mcmbrana propria, which 

 may be composed of stronger fibres of connective tissue, but which often looked as if 

 composed of circular muscular fibres. The wall of the oviducts, however, did not show 

 the same stronger outer wall ; it is composed of a distinct epithelium and a very narrow 

 or thin membrana propria. 



Whereas in Scalpettum vulgare each oviduct gives off a ccecum only once, and this 

 ccecum, which starts from the oviduct at the superior extremity of the peduncle, divides 

 again and again, the oviduct in Scalpettum regium penetrates into the interior of the 

 peduncle for about one-third of its whole length. In different places each oviduct in this 

 species gives off cceca, and these form together so voluminous a mass that the peduncle is 

 filled with it up to its inferior extremity. 



The oviduct of Scalpettum vulgare appears in a transverse section as an exceedingly 

 narrow slit, and 0'2 mm. in length. The oviduct of Scalpettum regium (PI. V. 

 figs. 8 and 9), in a transverse section shows an irregularly folded wall ; its largest 



(ZOOL. CHALL. EXP. — PART XXVIII. — 1881.) Ee 6 



