Specimen of Pelagonemertes Rollestoni. 379 



matter, consisting of large granules and oil-globules. The 

 contents of the diverticula were darker and more opaque, and 

 contained numerous clear oily globules of a bright yellow 

 and bright red colour, mingled with similar opaque globules 

 (fig. 4, a). The brightly coloured globules exactly resembled 

 those of the main tract. Similar coloured globules occur in 

 larval Nemertines ; and I have observed them also in a marine 

 Planarian larva, possibly that of a Thysanozoon, or the Pla- 

 narian larva described by Johannes Mtiller from the Mediter- 

 ranean, supposed to be that of Eurylejyta (Glaus, 'Grundziige 

 der Zoologie,' p. 286). 



The sac of the proboscis corresponded exactly with that de- 

 scribed in the adult. It was here found to terminate posteriorly 

 in a blunt point at a short distance from the hinder end of the 

 body. The fluid contained in it appeared transparent and 

 without corpuscles. The proboscis itself could be carefully 

 examined in the present transparent specimen. It was with- 

 out stylets and quite simple, invaginated in the usual manner ; 

 it was not seen fully protruded, but, when so protruded, must 

 be slightly longer than the animal's body ; it has an outer 

 pellucid gelatinous investment and an inner muscular layer 

 (fig. 5). No retractor muscle was observed to be connected 

 with it. 



The nervous system consists of two pairs of ganglia, of 

 which the upper are by far the larger and give off the stout 

 nerve-cords. The cords, stretching backwards on either side, 

 unite with one another above the rectum at the hinder end of 

 the body. The nerve-ganglia are shown enlarged in fig. 3. 

 No sense-organs of any kind were detected. On the outer 

 margin of the large superior ganglion (fig. 3) a series of elon- 

 gate pellucid cells were arranged side by side perpendicularly 

 to the curved surface which they form. Abundant fine nerves 

 were given off from the entire length of the nerve-cords to 

 the surface of the body, the muscles &c. arising both from the 

 inner and outer margins of the cords. At the origins of these 

 nerves from the cords there are very slight swellings on the 

 margin of the cord ; but these do not contain any nerve-cells. 

 The nerves are very fine, hyaline, with a nearly rectilinear 

 course, and they generally divide into two near their points 

 of distribution ; they are never tortuous or much ramified. 

 Terminal organs on the surface of the body in connexion with 

 the nerves were carefully sought for, but could not be found. 



A pair of vascular trunks follow the course of the nerve- 

 cords through the body, lying internally to them and beneath 

 them. The vessels unite with one another posteriorly, as do 

 the nerve-cords : their course is undulating. Just behind the 



27* 



