412 DE W. CARMICHAEL M'lNTOSH ON THE STRUCTURE OF THE 



might expect, from any other allied British form, such as Psamathe fusca, Johst., 

 and Castalia punctata, Mull., each of which possesses similarly jointed bristles, 

 and has the serrated terminal portion peculiarly clawed. In Psamathe the larger 

 size, the structure of the shaft, and the coarser serratures of the terminal portion 

 (Plate XVI. fig. 2), distinguish it from Castalia; while the latter again (Plate 

 XVI. fig. 1) has a much broader and proportionally longer terminal process than 

 the present form. The distinction in this respect between the Periboea and 

 Podarke of Dr Ehlers* and the latter is very apparent. Dr Grube's genus 

 Oorydromus,^ with which the foregoing has certain affinities, has also an unarmed 

 proboscis, but the feet are uniramous. 



I may also remark that two very distinct species, or rather genera, have been 

 included — on the one hand, by Dr Johnston in Britain, and on the other, by 

 several continental authors — under the name of Psamathe punctata. Some of 

 the most recent foreign publications— such as the work of Dr Ehlers and that of 

 Dr Malmgren — do not sufficiently recognise the distinctions between the two. 

 M. de Quatrefages,| however, correctly separates them into genera, yet he places 

 the synonym Castalia punctata, " CErst." under both. Dr Malmgren, § while 

 correctly including the Halimede venusta of Rathke || under Castalia punctata, 

 Mull., falls into the error of comprising Dr Johnston's species under the same 

 head — a slip which would not have happened if this excellent observer had seen a 

 specimen. Dr Johnston's species, for which, notwithstanding Dr Ehlers's views, 

 the original name of Psamathe fusca^ may be retained, has a uniramous foot, with 

 the terminal portion of the bristles characteristically marked shortly after its com- 

 mencement by a series of larger serrations, which gradually rise to a maximum, and 

 similarly diminish, before arriving at the middle of the process, into fine serrations 

 that disappear before the clawed tip is reached (Plate XVI. fig. 2). All the bristles 

 of the foot are not so boldly marked as this example, but in each there is a ten- 

 dency to have a shorter terminal piece, with coarser serrations, than in those of its 

 immediate allies, and the clawed portion at the tip is very distinctly seen, so that 

 the bristle can be distinguished specifically at a glance. The shaft has also coarser 

 transverse markings, and its distal end is somewhat less clavate than in C punctata. 

 The Psamathe cirrata of Prof. Keferstein,** also described by M. Claparede,| f 

 seems to me to be allied in the closest manner to P. fusca, if, indeed, it is not 

 identical therewith. M. de Quatrefages, however,]: J considers the annelids 



* Die Borstenwiirmer, &c. pp. 190 and 199, taf viii. 



t Troschel's Archiv fiir Naturges. 1855, p. 98. 



+ Anneles, vol. ii. 1865, pp. 100-102 and 106. 



§ Annulata Polychaata Spetsbergise, &c. 1867, p. 31. 



I Beitrage zur Fauna Norwegens, &c. (Nov. Act. Acad. C. L. C. Nat. Cur. &c), p. 168, 

 tab. vii. fig. 1-4. 



1 Loud. Mag. Nat. Hist. vol. ix. p, 15, 1836. 



** Zeitsch. fiir wiss. Zool. bd. xii. p. 107, taf. ix. figs. 32-36. 



ft Beobach. iiber Anat. &c. p. 55, taf. xiv. figs. 1-7. J J Op. cit. vol. ii. p. 41. 



