EEPOET ON THE SIPHONOPHOEJE. 171 



where it divides into the four radial canals. From the proximal base of this pedicular 

 canal arises a blind pallial canal, which ascends towards the dorsal median line of the 

 exurubrella, and ends near its apical part by a small csecal diverticulum (just as in 

 Lilyopsis). There is no inferior or descending pallial canal, as in Praya. 



Siphosome. — The long tubular stem of the cormus, which proceeds from the basal 

 opening of the hydrcecial canal (between the two lowermost nectophores), is beset in its 

 upper part with numerous buds of cormidia, and bears in its lower part a series of fully 

 developed sexual cormidia, separated by ecmal free internodes ; their number in the 

 specimen observed was about a dozen. Male and female alternate regularly. 



Cormidia,. — Each cormidium is essentially composed as in Erssea, of at least three 

 different medusomes ; firstly, a sterile medusome composed of a bract, a siphon, and a 

 tentacle ; secondly, a special nectophore ; and thirdly, a male or female gonophore ; the 

 latter bears a number of similar buds or reserve gonophores at its base. The entire 

 composition of the cormidia is very similar to those of Lilyopsis. The subumbrellar 

 cavity of the bract covers the greater part of the other organs ; these are placed as 

 usual, so that the siphon and its tentacle occupy the dorsal part of the cavity, the 

 special nectophore the ventral part, and the gonophores lie between them on both 

 sides. 



Bracts (fig. 26, from the right side ; fig. 36, from the left side). — The covering scales 

 of the cormidia, bracts or hydrophyllia, are very similar to those of Praya. They have 

 the form of a flat cap or an overturned boat, and are about 10 mm. long by 5 mm. broad. 

 Their ground-form is bilateral, more or less asymmetrical, their surface smooth, with 

 rounded edges. The upper convex face is compressed from both lateral sides ; the lower 

 face contains a deep irregular subumbrellar cavity, in which the organs of the cormidium 

 are partly hidden. The jelly-substance of the umbrella is much thicker in the ventral 

 than in the dorsal part of the bract ; it is thinnest on both lateral sides, which are deeply 

 cleft in the middle. 



Through the base of this deep lateral fissure passes the common stem of the siphosome 

 (a). The axial canal of this latter gives off a short branch to each bract, which forms 

 near the point of its attachment a small pyriform diverticulum (6c). From the base of 

 this phyllocyst arise four radial canals, which enter into the jelly-mass of the bract, are 

 irregularly bent, and end in a vesicular diverticulum. Two of these four canals are 

 odd, and lie in the oblique sagittal plane of the bract, a shorter ventral (cv) and a longer 

 dorsal (cd) ; the two others are paired lateral canals, and enter into the dorsal lobes of 

 the bract (right ex, and left cl). 



Siphons (figs. 2, 3, s). — The single polypite, which occupies the dorsal part of each 

 bract-cavity, has the usual form of siphons in Calyconectse. A thick-walled ovate 

 basigaster (s6) is connected by a short pedicle with the common stem (a). The large 

 ovate or pyriform stomach exhibits in its wall eight distinct orange-coloured liver-stripes 



