ASHWORTH, AN ACCOUNT OF ARENICOLA LOVENI KINBERG. 15 



logical work is not available, they have not been studied in 

 detail. Giant nerve fibres are present in the nerve cord, as 

 in all other species of Arenicola, except A. daparedii. 



A statocyst was found on each side of the type speci- 

 men, connected to the body wall by a strand of tissue, bnt 

 it could not be definitely ascertained whether this was a 

 solid cord of nerve and connective tissue or whether it con- 

 tained a narrow tubular structure. The former seemed more 

 probable as careful search failed to reveal any external aper- 

 ture at or near the point where the tissue strand meets the 

 body wall. When the Saldanha specimens came into my 

 hands serial sections were made of a statocyst and the adjac- 

 ent body wall of one of them, which definitely prove that 

 the vesicle has no opening to the exteriör (Fig. 8). The three 

 diameters of the lumen of this statocyst are 0,22, 0,2 and 0, 1.5 

 mm, respectively. The walls of the organ are thick, they 

 average about O^o? mm. in thickness. Each statocyst con- 

 tains a single round or oval statolith, the one in the serial 

 sections measures along two ^ of its diameters 0,0 8 8 and 0,075 

 mm. respectively. 



Diagnosis of Arenicola loveni Kinberg. 



The characters of this species may now be given thus: 

 — nineteen chaetigerous segments; thirteen pairs ofgills, the 

 first gill on the seventh segment, gills large and of the pin- 

 nate type; the median lobe of the prostomium is large, the 

 smaller lateral lobes are of almost uniform width, i. e., they 

 are not dilated or lobate at their anterior ends: neuropodia 

 are clearly visible on each segment, those of the branchial 

 and of the two pre-branchial segments are long dorso-ventrally 

 and almost reach the mid-ventral line; each notopodial seta 

 bears numerous finely toothed crests or »Sägeblätter», placed 

 at regular intervals along the distal third of the shaft, this 

 part of the seta has a striated appearance, as seen under 

 low magnification, and along one edge there is a well marked 

 lamina; five pairs of nephridia which open on the fifth to 

 the ninth segments; one pair of oesophageal glands, conical 

 in shape; two enormous muscular pouches project back- 



^ The third diameter cannot be accuratelv ascertained. 



