[ 73 ] 



V. On Valencinia Armandi *, a new Nemertean. 

 By W. C. M'Intosh, M.D., F.R.S.K, F.L.S. 



(Plate XVI.) 



Read June 17th, 1875. 



W HILE searching for a rare Annelid {Mesa mirabilis) that occurs near low water in 

 the extensive waste of sand at Southport, a slender thread, which glistened in the October 

 snn like gossamer, attracted notice in the upturned sand. This was the proboscis of the 

 ruptured Nemertean, which exists in considerable abundance in the sand amongst the 

 tubes of Laniee conchilega, associated with AmpJiiporus lactifloreus, A. hastatus, Micrura 

 fusca, and other forms usually characteristic of the laminarian and coralline regions of 

 the north. It appears to live in a burrow in the sand, and readily takes to a case or tube 

 in confinement. 



The body is 7 or 8 inches in length, and not much thicker than a stout thread. It is 

 rounded in front and in the middle, but becomes extremely flattened towards the tail, 

 which terminates in a somewhat lanceolate point. The anterior part of the body is 

 whitish, the posterior pale buff, while the tail is translucent. The head is rounded in 

 front, flattened, and slightly enlarged behind the tip. There is no trace of eyes, fissure, 

 or furrow. On the whole the Nemertean very much resembled Carinella linearis, from 

 Lochmaddy ; and it was placed in spirit under this impression. More careful scrutiny, 

 however, reveals that it properly comes near the genus Valencinia, De Quatrefages, 

 char, emend., the only British example of which ( Valencinia Imeiformis) was dredged in 

 numbers amongst the shell-gravel of Bressay Sound, in Shetland. The Zetlandic species 

 is larger, and has an evident row of eyes on each side of the head, besides other points of 

 distinction, which will by-and-by be alluded to. 



In the structure of the cutaneous system Valencinia Armandi agrees with its allies. 

 The entire surface is clothed with cilia ; and the cutis has the usual cellulo-granular 

 appearance (fig. 9, a), with numerous vertical streaks. The latter are not conspicuous in 

 the Zetlandic species (fig. 10, a), which has a minutely cellulo-granular cutis, very easily 

 removed in the preparations. In the new form the cutis is bounded externally by a some- 

 what definite edge, which probably represents a rudimentary cuticle. In the next layer 

 (b, figs. 9 & 10) a considerable difference exists between the two species. In Valencinia 

 Armandi the basis-layer is very thin, while in V. lineiformis it is dense. In the snout 

 of the former the cutis is proportionally thicker, but the basis-layer is not increased — 

 another contrast ; for the latter is especially developed on the snout in the Zetlandic 

 species. In V. Armandi there is an increase of this layer opposite the nerve-cords. In 

 connexion with the cutaneous system, it may be mentioned that, in a large Canadian 



* Named after M. Armand de Quatrefages, who long ago did such good work in the group. 



