222 Mr. F. E. Beddard on 
dilated, and indeed in the region behind the glands dwindles 
so much in size as to be almost invisible. 
These glands I regard as homologous with the “ kidney- 
shaped” glands recently described by me in Pleurocheta*, 
These are the only two genera, so far as I am aware, in which 
any thing of the kind exists. They probably represent a 
specialized condition of the intestinal ceca of the Leech and 
certain Polycheta such as Aphrodite. In the latter genusf, 
moreover, the ceca are branched, and thus present a nearer 
approximation to the complex glands of Pleurocheta and 
Typheus. The two cxea of Megascolex, first noticed by 
Vaillant t in Megascolex cingulata, and subsequently described 
in several other species of the same genus by Perrier§, belong, 
no doubt, to the same category, and represent in a very rudi- 
mentary way these same glands. 
The genus Megascolex itself, however, contains individuals 
which in this respect are more specialized ; two species, Mega- 
scolex Steboldii and M. musicus, possess no fewer than six 
pairs of these ceca ||. 
The ctrculatory system consists of a dorsal and a ventral 
vessel united by six transverse trunks or “ hearts” in seg- 
ments 9-14; of these the two posterior are slightly larger 
than the others. 
The nervous system closely resembles that of other earth- 
worms; the cerebral ganglia, hardly separated from each other, 
are placed on the line of division between the buccal cavity 
and the pharynx in the 2nd segment of the body. The 
ventral chain commences in the 3rd segment; the two or 
three anterior ganglia are considerably larger than the follow- 
ing ones and closer together; the ganglion occupying the 17th 
segment, and lying between the male generative apertures, is 
also, as usual, of larger size than the rest. From each — 
ganglion two pairs of nerves appeared to take their origm— 
one at the anterior, and the other at the posterior extremity. 
Segmental organs.—Instead of the ordinary simple tubes 
opening into the body-cavity bya ciliated funnel which arefound 
in the common earthworm and the majority of the Oligocheta, 
there are in Typheus a series of tufted glandular masses 
somewhat similar in appearance to the tufted glands which 
are almost universally found in the genus Megascolex, and re- 
figs. 1, 11, 12, pl. xxvi. fig. 19. 
+ Gegenbaur, Man. d’Anat. compar. (trad. frang. par C. Vogt), p. 206, 
figs. 43, 44. 
{ Vaillant, Ann. des Sc. Nat. 5 sér. t. x. p. 233, pl. x. fig. 4g. 
§ Perrier, Nouv. Arch. du Muséum, p. 10], &c. 
|| Horst, Notes from the Leyden Museum, vol. v. pp. 192, 194. 
