82 CRLORMMIDM. 



penultimate may have none. The distinctions between the gills of the young or adolescent 

 forms and those of the adults is marked, the latter being much thicker, coarser, and 

 denser. The body tapers a little posteriorly and ends in a conical caudal region of about 

 five rings, the terminal having the anus in the middle. 



Fauvel (1899) holds that this was the form described as Arenicola branchialis by 

 Audouin and Edwards, whose name therefore has priority, but their insufficient and 

 inexact description gave rise to ambiguity, so that he thinks the more recent name, 

 A. Grubei, should stand. This author x was formerly inclined to consider Branchiomaldane 

 as a stage in the development of Arenicola branchialis, but Ashworth's recent investiga- 

 tions would indicate its independence. The three species described by Cerniavzsky refer 

 to this form. The A. nodosa of Leach in the British Museum is, according to Ash worth, 

 a typical dark example of A. branchialis. 



Schiller 2 (1908) gave a careful account of the vascular supply of all the organs in 

 Arenicola branchialis. 



A small form, procured between tide-marks, along with a Maldanid under a stone at 

 St. Peter Port, Guernsey, July, 1868, approaches Arenicola. Anteriorly the proboscis is 

 extruded, and it somewhat resembles that of Arenicola with its papillse and muscular 

 arrangements. On the region immediately behind the foregoing are two globular or 

 rounded protuberances, neither of which appear to represent the tip of the snout of 

 Arenicola. Simple bristles occur in front, and vertical rows of minute hooks, after the 

 manner of Arenicola, posteriorly. 



Family XIX. — Chlor^mim;, Malmgren. 



Pherusea, Grube ; Siphonostomeds, Johnston ; Ghlordemiens, De Quatref ages ; Pheru- 

 siens, Claparede. 



Cephalic lobe short, often withdrawn into the buccal, with two grooved tentacles 

 superiorly. Buccal segment short, or produced into a short retractile tube; bristled; 

 branchia3 dorsal, filiform, short, more or less numerous, attached to the buccal lobe or its 

 tube. Bristles of the anterior segments form a guard or cage for the cephalic region. 

 Body vermiform, more or less tumid anteriorly, or sub-fusiform and short ; surface with 

 muciparous papillaa ; segments comparatively few. Covered with a coating of mucus or 

 with grains of sand, also extending to the papilla. Blood green ; intestine longer than 

 the body. Coelom with few dissepiments. Feet biramous. Bristles issuing from the skin 

 itself, rarely from processes, articulated ; superior capillary, inferior strong and short 

 (crotchets), sigmoidal, or with hook-like tips, few. Dorsal and ventral bristles of the 

 first few segments linear, generally stronger, longer, brilliantly iridescent and arranged 

 in a transverse series, whilst each is articulated in a characteristic manner. 



In the structure of the body- wall the longitudinal muscular fibres, both ventral and 

 dorsal, in Stylarioides plumosa are thin, and in dilated specimens the separate bands of 



1 ' Compt. Eend. Acad. So,/ Paris, t. cxvii, p. 733. 



2 ( Ueber den feineren Bau der Blutgefarse bei den Arenicoliden/ op. tit., pp. 293—320. 



