842 MR JAMES RITCHIE ON 



individuals are of the typical, single-jointed form of Pedicellina gracilis, although 

 they seem to be rather less than normal examples ; but associated with them are a very 

 few individuals with stems composed of two internodes — the variety nodosa of Lomas, 

 the type specimens of which were obtained from approximately the same neighbour- 

 hood. From these it is clear that gracilis and nodosa are one species. 



Further, as to the relationship between P. gracilis and P. belgica : — In some respects 

 the figures of the latter species by van Beneden are obviously inaccurate. Thus, 

 although describing " des cloisons ou diaphragmes au coeur de la tige, qui la divise en 

 compartiments distincts," # he omits to indicate those nodes except in a solitary case, 

 and there the position is abnormal. It is not surprising, therefore, to find that no 

 nodes are indicated in the stem between the muscular swellings, although such exist. 

 Since muscle-strands are confined to the swellings of the stem, the representation and 

 description of "des cordons musculaires dans toute la longueur" is faulty, as also is 

 the uniformity of thickness which is figured for the cuticle. Allowing for such in- 

 accuracies, it is difficult to avoid concluding that Pedicellina gracilis and P. belgica 

 are one. The habits of the two are similar, and the only structural differences appear 

 to be that the former has "about twenty" tentacles, although Gosse counted fifteen, t 

 and my specimens have fourteen or fifteen, while the latter is said to have only twelve, 

 although in the contracted specimens of P. belgica I have examined this number was 

 certainly sometimes exceeded. Again, in Foettinger's estimation, the basal expansion 

 of the stem in P. gracilis is very long compared with that of P. belgica. But Hincks 

 observes that in P. gracilis " the basal cylinder varies in length, and in the proportion 

 it bears to the rest of the stem," while in P. belgica there is also a considerable amount 

 of variation in these dimensions ; indeed, in the specimens of P. gracilis which I have 

 examined, the basal cylinder is less than that of P. belgica. 



It seems to me, then, that no differences sufficient to separate these two species 

 exist, and, therefore, that Pedicellina belgica must be merged with P. gracilis. 



Judging from the description and figure of Jullien and Calvet,J I can find no 

 distinction of specific significance between their Barentsia Berenice from Newfoundland 

 and the simple stages of Barentsia gracilis. It seems very probable that any species 

 with a basal muscular bulb (musculium) and a rigid chitinous stalk (pediculium) ending 

 in a flexible fleshy portion (pedicellium) — such a type being known as Barentsia — can 

 generate from the last portion a new segment, and so come within the sweep of Ehlers' 

 genus Gonypodaria. The closeness and the apparent normality of the relationship 

 between the uni- and poly-jointed individuals render superfluous the latter genus, 

 which falls within the signification of Barentsia.^ 



* Van Beneden, " Reclierches sur l'anatoniie, la physiologie et le deVeloppenient des Bryozoaires, qui habitent 

 la cote d'Ostende," Nouv. Me'm. Acad. Roy. Bruxelles, t. xix., 1845, p. 24. 



+ Gosse, P. H., A Naturalist's Rambles on the Devonshire Coast, London, 1853, p. 217. 



} J. Jullien and L. Calvet, "Bryozoaires provenant des canipagnes de YHirondelle" (1886-1888), in Re's. camp, 

 sci. Albert I. Monaco, fasc. xxiii. p. 26, pi. ii. fig. 2. 



§ See also Waters, A. W., in Re's. Voy. S.Y. Belgica: Zoologie, "Bryozoa," Anvers, 1904, p. 100, 



