64 NILS HJ. ODHNER, MOLLUSCA. 
habits. He remarks the resemblance of this form to J'riionia and considers it a 
connecting link between the Janidae and the other Aeolididae. As his account of 
its morphology is very short, a more complete description may be given here, based 
on the present specimen, which was examined both in toto and in sections. 
As to its exterior shape, the dorsal side is occupied by a large notaeum, which 
surrounds and extends beyond the foot and the head. Near the hinder end of the 
body, this notaeum passes directly into the foot, its margins on both sides being 
connected with the foot end. The margins of the notaeum are set with papillae all 
round, these are smaller at the edges and become larger towards the centre; in the 
middle part of the back they are replaced by minute papillae; such also occur be- 
Fig. 16. Rhinophore of Madrella Fig. 17. Dorsal papilla of Madrella 
ferruginosa A. & H., from front ferruginosa A. & H 
and from side. 
tween the rhinophores, without, however, forming any feature that might be regarded 
as a rudimentary crest, such as Exror has observed in large specimens. The under 
surface of the notaeum is quite smooth. 
The rhinophores (fig. 16) somewhat resemble those of a T'ritonia, as Evior 
remarks. A short peduncle bears a club divided into leaf-like lobes or tubercles, 
arranged round a subcentral tip, projecting beyond the tubercles. In the front 
side the peduncle carries an obscure furrow running from top to base. On its hinder 
side the peduncle is wrinkled by some semicircular lamellae, which disappear on its 
front side; these may perhaps be due to contraction. The rhinophores are not 
retractile and have no sheaths. 
At the base of the rhinophores, on their inner side, a small eye is visible, by 
its pigment shining through the epidermis (fig. 21 0). 
The anterior corners of the foot are angular and only slightly projecting. They 
are free from the velar expansion around the mouth. This velum is semicircular and 
produced on each side into a rounded lobe. Towards the median line, the lobes are 
attached to the front margin of the foot. The velum projects quite freely from 
the neck and is free from the notaeum. 
On the right side of the body are visible the genital opening in the first third 
and the anal orifice in the last third of the body length. The renal pore is situated 
between these two, somewhat nearer to the anus. 
