Afterwards I hope to give a more detailed account of this for a new species of Chaetoderma 

 (Chaetoderma canadense) where even the ganglion |)Osterius superiiis is found in the heart itself 



The heart consists of i atrium, which has a double origin, on account of 2 invaginations 

 of the wall of the distal pericardial ollsels, wliich unite (fig. 201 a). This atrium is spacious and 

 provided with a tolerably thick wall. The ventricle on the contrary is an invagination of the 

 dorsal pericardial wall and in communication with the atrium. ?dy sections do not permit of a 

 more accurate observation ot the heart. 



The gills, which are broad and short, contain 8 or 1 2 gill-lamellae only. 



The animals are males and the genital glands are fully mature. The latter and the 

 cloaca-ducts do not offer any peculiarities. 



Chaetoderma Loveni differs in many respects from the species of Chaetoderma already 

 known. It is clearly distinct from Chaetoderma nitidulum on account of its radula with the 

 numerous teeth, and it differs likewise from Chaetoderma radulifera, which possesses a much 

 more developed radula. The radula of Chaetoderma gutturosum is more closely related to that 

 of Chaetoderma Loveni, though there is a difference between the two. Besides the shape of 

 the spicula shows that we have to deal with a different species here. 



13. ChactoderDta Wirciii nov. spec. (Plate VI, figs. 204 — 210). 

 Stat. 241. 4°24'.3S., 129° 49.3 E. 1570 M. i Specimen. 



Length 11 mm. Length-index of the only badly preserved specimen 11. I'ro.ximally 

 slightly broader than distally. Colour greenish-brown. Spicula larger than those of Chaetoderma 

 Loveni and more lance-point-shaped. Radula witli i large tooth, 2 chitinous side-pieces, 2 

 chitinous sickle-shaped teeth and some smaller ones(?). 4 salivary glands. Liver large as in 

 Chaetoderma nitidulum. About 20 gill-lamellae. 



East-Indian Archipelago, i Specimen. 



The length is 11 mm.: the diameter proximally over i mm., distally i mm. The length- 

 index is II. The proximal end is bluntly cut off and the animal glitters owing to the thin spicula. 

 At the distal end there are also a number of .straight, long spicula. Thi- colour is a greenisli- 

 brown. The mouth-opening is round and the liver shows through distinctly. Of the internal structure 

 I can give only very unsatisfactory information; the anterior jjortion has been well-preserved, but 

 the case is different with the posterior part, the organs of which are hardly perceptible. 



Fig. 204 represents the animal 4 times enlarged. The dorso-terminal sense-organ is 

 large and extends as in Chaetoderma jjroductum as far as the cloaca-border. 



In appearance Chaetoderma Wireni differs greatl)- from Chaetoderma Loveni. When only 

 slightly enlarged the differently shaped spicula become directly obvious; they are much larger 

 here. In fig. 205 A the spicula of the body-wall are 75 times enlarged and show the difference 

 from fig. 183, also 75 times enlarged. The shape of the spicula is more pointed here; they 

 are ribbed length-wise. Fig. 205 B represents a spiculum of the posterior end, C the spicula 

 around the mouth-opening, present in great numbers. The cuticle is thicker than that of 



