14 SIR CHARLES ELIOT 



high, outside. They are not at all caducous, or even easy to detach. They are not set 

 in groups, though the undulation of the dorsal margin produces a superficial appearance 

 of such an arrangement, but are all crowded close together, except a few large ones 

 which stand further inside, 2-3 mm. from the rest. The bare space in the middle of 

 the back measures 15-20 mm., and the row of cerata which forms the border, though 

 very irregular, is generally four or five deep, and consists of two large and two or three 

 small ones. The shape of the cerata varies greatly. Some are symmetrically tapering, 

 some cylindrical with blunt tips, and some, particularly the larger ones, are swollen at 

 the bases, and taper somewhat suddenly in the upper half. The outline is irregular, 

 and often presents knots and projections. The hepatic diverticula within the cerata 

 are, like the cerata themselves, of irregular outline, and covered with knots, but are not 

 ramified. They are similar in substance to the liver in the body, and in colour vary 

 from brown to dull pink. In many cerata, at any rate, the liver cavity communicates 

 with a small cavity above, which, in its turn, communicates with the exterior by a pore, 

 which is sometimes visible externally. This cavity contains nematocysts of two 

 shapes, spherical and elliptical. Mr G. H. GROSVENOR, who has made a special study 

 of these organs and kindly examined for me some from Notaeolidia gigas, informs me 

 that the spherical nematocysts contain a convoluted cord inside and are of a type 

 found in actiniae. In the elliptical nematocysts the cord is hard to see, but, as far as 

 it can be followed, is straight. 



The large pericardial prominence lies a little to the right of the centre of the back, 

 and is 18 mm. long by 14 broad. The genital orifices are about 38 and the anal 

 papilla 52 mm. from the anterior end. This papilla lies just under the cerata, and its 

 margin bears five crenulations, which are perhaps not natural. 



On opening the body, the large heart is seen. It appears to be as usual. On the 

 auricle are two lumps, possibly glandular. Considering the size of the animal, the 

 central nervous system is small, the eyes in particular being minute specks. The 

 ganglia are yellowish-white, and arranged as usual in the Aeolididae. The cerebro- 

 pleural ganglia are elliptical, the pedal rather rounder. On the buccal commissure are 

 situated the two elliptical buccal ganglia, separated from one another by a considerable 

 interval, and connected with the gastro-oesophageal ganglia. The other commissures 

 appear to be united in a common sheath. 



The buccal mass measures 11 mm. by 14. The front part of it is formed by 

 two moderately elongate jaws, which do not enclose the sides. They are brownish- 

 yellow, and not very strong. The length is 8 mm. ; the breadth 6 mm. at the top, 

 3 at the bottom. The masticatory process is 3 '2 mm. long; the edge is not denticu- 

 late, though it bears a few lumps and irregularities here and there. 



The radula consists of eighteen rows of yellow teeth, and this number was constant 

 in the five specimens dissected. Each row consists of a central tooth and normally 

 four laterals. In some rows the outermost lateral is lost, and in one or two there appears 

 to be a fifth rudimentary plate. The radula is brittle, and the central tooth liable to 



(ROT. soc. EDIN. TRANS., VOL. XLI., 522.) 



