REPORT ON THE DEEP-SEA MEDUSA. 139 



cruciform hollow space found in the middle of the arm disk, and from which the eight 

 arm canals run out downwards (ch). These lie adradially, but in pairs, above the eight 

 limbs of the tufted rosette, and must be regarded as distal bifurcate branches of the four 

 perradial pillar canals. Each arm canal immediately divides into three narrow canals, 

 which run parallel to the ends of the three corners of the arm ; one of them lies ventrally 

 or axially, the two others dorsally or abaxially. Hence it comes that the whole free, 

 triangular part of the arm must be regarded as the under arm ; only the short basal part 

 of the arm, containing a simple canal, which is fused with the arm disk, corresponds to 

 the upper arm of the Rhizostomse multicrispae. Numerous branches run from the axial 

 or ventral canals of the arms up to the tufts of the oral rosette (ab') and down to the 

 ventral funnel frill of the distal bunch of tufts (ab 3 ). The two axial or dorsal canals are 

 only branched below, and this branch runs on the two dorsal funnel frills of the bunch 

 of tufts. The distal ends of the three arm canals run in the three wings of the 

 triangular terminal knobs so far as the point where they seem to open by a common 

 terminal aperture. 



The peripheric coronal intestine shows essentially the same conditions which I first 

 described in Crambessa tagi (1869). Sixteen strong radial canals pass out from the 

 periphery of the cruciform central stomach, run in the subumbrella to the umbrella 

 margin, ramify thickly, and form a delicate, vascular network. Of the sixteen 

 canals, the shortest are the four perradial, which spring from the distal end of the four 

 limbs of the gastral cross (immediately above the four pillar canals), and which widen 

 like an ampulla at their proximal base (fig. 4, cp). The four mterradial canals are the 

 longest ; they spring from the corner between every two limbs of the gastral cross, and are 

 beset with csecal diverticula (fig. 4, ci). The eight adradial canals are shorter than the 

 latter and stronger than the former ; they spring from the two corners of the distal end 

 of the limb and diverge in the form of an arch towards the umbrella margin. All the 

 sixteen canals are connected by a strong coronal canal (fig. 4, cc). This hies in the 

 subumbral coronal furrow, which separates the central umbrella disk from the velarium. 

 The peripheric vascular network is divided by the coronal canal into two different 

 sections, of which the narrower lies inside the coronal canal, and the broader outside. 

 The intracircular vascular network is only 4-6 mm. broad, fills the space between 

 coronal canal and the distal ends of the limbs of the cross in the form of a narrow 

 zone, and consists of from three to four rows of loose meshes, irregularly polygonal in 

 shape. The extracircular vascular network is three times as broad (12-16 mm.), consists 

 of an extremely fine thin mesh work (whose finest meshes are hardly visible to the naked 

 eye), and fills the whole subumbral side of the velarium, from the coronal canal, as far as 

 the thin margin of the marginal lobes (fig. 4). 



The genitalia (PI. XXXII. figs. 1-6, s) in Leonura show, on the whole, the same 

 conditions of form and structure which Grenadier and Noll (1876) described minutely in 



