igii.J F. H. Stewart : Development and Anatomy of Cirripedes. 45 



portions of the canal, are empty. The two caeca arising from the anterior end of the 

 canal are present. 



Nervous system. — -There is a pair of large cerebral ganglia and a massive ventral 

 nerve cord. The hairs which cover the outer surface doubtless fulfil the usual sensory- 

 function — vide infra, p. 16. 



Reproductive system. — The testes occupy the same position as in Scalpellum 

 squamuliferum, that is, one on either side of the stomach. At the root of the prosoma 

 there is a somewhat indefinite space, which may possibly be the equivalent of the 

 rostral duct. There are no cells which it is possible to recognize as ovarian. 



The cement glands are two groups of cells, identical with those of 5. squamulife- 

 rum, which are to be found in the second quarter of the length of the peduncle 

 counting from above. As in 5. squamuliferum many of them contain the large 

 irregular yolk-like granules which stain intensely with haematoxylin . while a smaller 

 number are without these. Ducts were not found. 



The yolk also appears in the peduncle just as in 5. squamuliferum. It, however, 

 tends to lie more above than below the cement glands. In some cases the yolk 

 masses appear to be lying actually within cells, — -vesicular cells with flattened nuclei, 

 — the yolk mass filling up the ve^^icle. 



It is a noteworthy fact that two species in which the hermaphrodite forms 

 resemble each other so closely as S. squamuliferum and beitgalense shouldpossessmales 

 which differ to such a degree. 



V.-POST-LARVAL DEVELOPMENT OF THE MALE OF 

 SCALPELLUM GBUi ELIL, ANNANDALE. 



(i) The cyprid Larva. 



It closely resembles in its structure the cyprid of 5. regium described by Hoek.^ 



Plate vi, fig. 8, represents a cyprid after attachment but before the first post- 

 larval ecdysis. It measures i mm. in length, -6 mm. in height. The prosoma bears 

 six pairs of jointed legs. In comparing it with the slightly older stage of 5. squamu- 

 liferum in which the ecdysis is in progress, various differences due to the increased 

 degeneracy and specialisation of the male adult will be noticed. The alimentary 

 canal is reduced to a closed oesophagus (pi. vii, fig. 2, oes.) andasmall sac-like stomach 

 (pi. vi, fig. 8, St.) with two blimt forward prolongations representing the caeca (pi. vii, 

 fig. 2, St.). There is no hind gut or anus. 



The nervous system is still well developed , but the segmentation of the ventral 

 nerve cord {v.n.c, pi. vi, fig. 8, and pi. vii, fig. 2), if present, is not perceptible. The 

 nerve cord appears twice in the transverse section represented in pi. vii, fig. 2, owing 

 to the curvature of the prosoma. I have not found larval eyes in the cyprid. 



The testis (pi. vi, fig. 8, and pi. vii, figs, i and 2, /.) is relatively much greater. 

 It occupies the space given up to the stomach and intestines in 5. squamuliferum. It 



^ Compare Hoek, 8, p. 7. 



