90 THE VOYAGE OF H.M.S. CHALLENGER. 



sinus (cs) which only communicates with the central stomach by the four perradial 

 gastral openings, is divided a little above the middle into four quadrants by the four 

 inter radial septal nodes (fig. 1, hi). These " cathammal nodes " are only a few millimeters 

 large, but consist of very firm fibrous cartilage (cornp. above, pp. G7, 80 ; and PI. XXV. 

 fig. 8). The peripheric pouch corona, into which the coronal sinus opens at its lower 

 margin by sixteen tranverse clefts (at the upper margin of the coronal muscle), is divided 

 by the sixteen subradial lobe clasps into sixteen coronal pouches ; and each of these is 

 subdivided by the invagination of the tentacle funnel into an inner and an outer coronal 

 pouch (axial velar pouch and abaxial avelar pouch). Besides these, each coronal pouch 

 gives out two lobe pouches below, which compose the marginal " festoon canal " ; and 

 whilst each of the four interradial coronal pouches sends an ocular pouch to the sense 

 club, each of the twelve remaining coronal pouches sends out a wide tentacle canal into 

 each tentacle (comp. above, p. 81, and the explanation of PI. XXV. fig. 1). 



Genitalia (PI. XXIV. fig. 1, sf). The fragment before me belonged to a mature 

 female, but only one pair of the four pairs of reproductive glands was preserved. The 

 two ovaries of this pair showed the situation and form represented in the middle of fig. 1. 

 They lay between the gastral openings in the subumbral wall of the coronal sinus, whose 

 upper and lower margin they almost touch with both ends. Both ovaries of the pair Lie 

 almost parallel beside each other in the upper half, and are only separated by the narrow 

 intergenital muscle (5 mm. broad). On the other hand they diverge strongly in the lower 

 half, as there the triangular interradial deltoid muscle (md / ) is inserted between them. 

 The distance between the lower ends amounts to 50 mm. Each of the eight ovaries 

 forms a narrow horseshoe-shaped arched genital band, whose convex distal arch nearly 

 touches the upper margin of the coronal muscle (mc') below, whdst the two parallel 

 limbs, which lie close together, almost reach above to the pylorus (gy). The thickened 

 supporting plate of the subumbrella forms a projecting midrib (" sterigma, costa 

 genitalis," st) in the middle between the two limbs. The genital band is raised on both 

 sides into a series of folds, which project internally into the urnbrella cavity and 

 externally into the coronal sinus (figs. 5, 6). The number of these broad folds, which are 

 subdivided like a fan into smaller folds (figs. 5, 6), amounts from 40 to 50 in each ovary 

 (20 to 25 in each limb). They are 4-6 mm. long, 2-4 mm. broad, and closely packed 

 with spheroidal ova. The smallest ova lie at the basal margin of insertion of the folds, 

 the largest at the freely projecting margin, which is turned towards the " costa genitabs " 

 (st). At the basis of the folds we see clearly that the smallest and youngest ova 

 originate immediately from the encloderm cells which line the subumbral wall of the coronal 

 sinus. As soon as the ova grow to a certain size, each ovum becomes enclosed in a 

 gelatinous fulcral sheath (fig. 7, yz), a superficial abaxial growth of the supporting plate 

 of the subumbrella (»•:). In transverse sections, through the genital folds, we see the 

 ova, enclosed in these fulcral capsules, lying in rows beside one another (fig. 7). The 



