10 ARKIV FÖR ZOOLOGI. BAND 7. N:0 5. 



a transversely striated appearance, which is well seen even 

 under low magnification (aboiit 50) and forms a very striking 

 feature of the notopodial setae of A. 1 oveni (Fig. 3). Kinberg 

 has clearly indicated the transverse striation in his figure 

 (IG, S.) of a seta. 



The well-marked striation and the high degree of devel- 

 opment of the crests are tvvo characteristic features by which 

 the notopodial setae of this species may be readily distinguish- 

 ed from those of any other species of Arenicola. 



Crotchets from the nineteenth neuropodium of the type 

 specimen are about 0,7 5 mm. long (Fig, 5, A). The distal 

 end of the crotchet bears no teeth behind tlie rostrum and 

 there is a wide angle — about 130° — between the rostrum 

 and the shaft. Both these features are characteristic of the 

 late growth phases of the crotchets of Arenicola. The crot- 

 chets (Fig. 5, B) of one of the Saldanha specimens were also 

 examined, and compared directly with those of the type spe- 

 cimen with which they closely agree, the only difference being 

 that, in the former, the angle between the rostrum and shaft 

 is a little wider. 



It is so constantly the case, in all species of Arenicola, 

 that the crotchets present in the same neuropodium are 

 practically uniform in build, that the occurrence of an in- 

 stance to the contrary is worthy of note. In the fifteenth 

 neuropodium of one of the Saldanha specimens there are 115 

 crotcliets, among which is one which differs from the rest in 

 its more slender form; it is of the same length and curva- 

 ture as its felloAvs but is only about 28 m. in diameter in the 

 middle of its shaft, whereas the corresponding portion of the 

 neighbouring crotchets is 43 a in diameter. This slender 

 crotchet and the next one to it are drawn in Fig. 6. They 

 are from near the middle of the neuropodium and the rostrum 

 of the stouter one is rather worn away at its tip. 



The crotchets of A. loveni are intermediate in their char- 

 acters between those of large examples of A. marma and 

 A. cristata, but more neariy approach the latter. 



Gills. 



There are in each specimen thirteen pairs of gills, the 

 first pair being situated on the seventh segment. In all the 



