iEGIRUS. 



each row : the median spine is deficient, and the tongue is divided down the centre by a narrow 

 naked space. The tubular portion behind projects a little backwards from the buccal organ. 

 A pair of tubular salivary glands open into the mouth at the sides of the oesophagus. This 

 latter organ is rather short, and passes from the upper posterior end of the buccal mass : it is 

 of equal caliber throughout, with the exception of a slight swelling immediately after it passes 

 through the nervous collar : it enters the liver in front, to join the stomach, which is small, and 

 buried in that viscus. A portion of the upper surface of the gastric pouch is seen, however, 

 emerging upwards from the biliary organ, and gradually subsiding into the intestine, which 

 is short. At the junction of this tube with the stomach, there is a small oval sac — a rudi- 

 mentary pancreas — and at the other extremity, a gland-like body ; but this latter does not 

 appear to be connected with the alimentary tube, and we have not succeeded in determining 

 its nature. 



The reproductive organs are much like those of Tolycera. The testis is composed of a 

 tubular, and a large, irregularly rounded, glandular portion ; the intermediate thin duct-like 

 tube not being present. The spermathecee are oval, the principal one being large, the other 

 very small. 



There is nothing peculiar in the vascular system, so far as we have been able to examine 

 it, and the renal organ, though observed, has not been sufficiently made out. 



The nervous system is more highly concentrated than in Tolycera. There are only two 

 pairs of principal oesophageal ganglia, — the cerebroid and branchial being completely fused, 

 so as to form, above the alimentary tube, two large reniform masses, which are united to each 

 other by a very short commissure across the median line. The anterior portions of these 

 masses represent the cerebroids, and accordingly each gives off from the frontal margin three 

 nerves, which supply the channel of the mouth and the oral tentacular appendages. The 

 olfactory ganglia ' are large and oval, being equal in size to the buccal ; they are closely 

 adherent to the frontal margin of the same ganglia, but a little nearer to the median line. 

 The nerves they supply are stout, and go direct to the dorsal tentacles. The posterior portions 

 of the large central masses are the branchial ganglia, and from the outer margin of each a couple 

 of nerves are sent off, which, branching forwards and backwards, go to the dorsal skin : the 

 anterior branch supplies the veil or mantle-border overhanging the head. From the right 

 branchial, two additional nerves are given off ; one of which, coming from the outer margin, 

 passes to the male sexual organ ; the other is given off from the under side. These are all we 

 have detected of the visceral nerves. The pedial ganglia are rounded in form, and are closely 

 attached to the outer margin, below, of the two large central masses : they are placed at the 

 sides of the oesophagus, and are united below that tube, by a rather long, stout cord, — the 

 great oesophageal collar, composed, in this instance, of three filaments, two of which are, as 

 usual, pedial — one branchial : three nerves are given by these ganglia to the foot. 



The buccal ganglia present nothing unusual ; they are joined together across the median 

 line by a short commissure. The gastro-cesophageal ganglia have not been observed. 



The eyes are sessile on the outer margin of the anterior or cerebroid portions of the central 

 ganglionic masses. The auditory capsules are attached to the under side of the same portions 

 immediately behind the eyes, and contain numerous elliptical otolithes, and a single spherical 

 one, much larger than the others. 



The skin is tough and coriaceous, having the imbedded spicula much more crowded than 

 in any other of the Polycerina : they are fusiform, pointed at both ends, and bent in the centre. 



