232 POECILOCH^TUS. 



a loop in the anterior region, and which open externally between the second and third 

 bristle-bundles, apparently at the posterior part of the second segment. The exact 

 situation of the inner opening is uncertain. In ripe forms simple, clavate, ciliated tubes 

 are found in those segments having gonads. Further investigation is needed as to their 

 history. The series are separate. The sexual elements appear to be developed in the 

 posterior segments. The nerve-cords present a neural canal at the upper and inner 

 region of each in section (Fig. 124 a). 



Habits. — It is less hardy than Haplobranchus, and apparently less able to live in 

 brackish water diluted by heavy rain-showers. It is recognised by its vermiform move- 

 ments, its red colour, and the waving tentacles. 



It forms a loosely coherent tube by gathering up particles of mud around it, probably 

 by aid of mucous glands. 



Spionid Z, with horny proboscis. Plate CV, figs. 5 and 5a — bristle and hook. 



A crushed fragment of what appears to be a representative of this family or allied to 

 it, was procured by Dr. Gwyn Jeffreys in the ' Triton ' in 1883. Locality not stated, but 

 probably in deep water in the Atlantic. It has the peculiarity of a horny wall to the 

 proboscis. 



The foot in the dorsal division bears tufts of pale golden, nearly straight, capillary 

 bristles of considerable length, finely tapered almost from the basal third to the tip, 

 and marked by longitudinal stria3 (Plate CV, fig. 5). The inferior division has ventrally 

 two or three long, curved dotted bristles, and a series of winged hooks (Plate CV, 

 fig. 5 a) with narrow necks and the wings truncated at the tip. The main fang 

 seems to be grooved or striated, and with a well-marked spike on the crown in lateral 

 view. The length and slenderness of the shaft of these hooks differ considerably from 

 the ordinary type of the Spionids, and the position here assigned to the fragment is quite 

 provisional. 



The example is a female with partially developed ova. 



Genus CVI. — Pcecilooh^tus, Claparede, 1863. 



Prostomium simple, with one anterior median tentacle. Nuchal organ in the form 

 of three tentacle-like processes arising from the posterior border of the region. Dorsal 

 cirrus of the first segment well-developed, ventral rudimentary. Both cirri from the 

 seventh to the eleventh (or thirteenth) segment flask-shaped, with long stiff necks. 

 Anus dorsal, with two long and two short cirri. Branchise on the feet from the twenty- 

 first segment backward. Dorsal blood-vessel with large lateral pouches in segments 

 twelve to fifteen. Bristles from the seventeenth segment backward have long hairs. 

 In the posterior region the dorsal bristles have assumed the form of stout hooks in 

 transverse rows. 



This genus owes its origin to the acuteness of Claparede, 1 who in 1863 found many 

 1 'Beobacht./ p. 77, Taf. vi, figs. 1—11, 1863. 



