TEREBELLIDAE i8i 



Genus Pista, Malmgreri 



One to three pairs of branchiae with a well developed main trunk. Lateral lobes in 

 the anterior region. Notopods begin on the fourth segment and neuropods on the fifth. 

 Bristles smooth. In the first few neuropods the hooks have long shafts. In the rest of 

 the body they are avicular and in double rows over a certain number of segments. 



Pista mirabilis, Mcintosh. 



Mcintosh, 1885, p. 454, pi. li, figs, i, 2; pi. xxviiA, fig. 34; pi. xxxviiiA, fig. 2. 



Scione mirabilis, Benliam, 1921, p. 85, pi. ix, figs. 97-100. 



Pista mirabilis, Benham, 1927, p. 99, with synonymy. 



Monro, 1930, p. 186, fig. 76. 



Scione spinifera, Ehlers, 1908, p. 152, pi. xx, figs. 10-14. 



Pista spinifera, Augener, 1932A, p. 60. 



Occurrence. St. 363 (i); WS 244 (2 with cluster of tubes); WS 245 (numerous); WS 246 (i); 

 WS 871 (numerous with tubes). 



Specific characters. A single pair of gills. Large lateral flaps on the third segment 

 and small ones on the fourth. There are 17 thoracic chaetigers and the gland shields 

 extend to about the thirteenth. The bristles are narrowly bordered capillaries. The 

 special hooks of the first thoracic torus have very long shafts and no denticles above the 

 main fang. The normal uncini of the rest of the body have two to three rows of denticles 

 above the main fang. The tubes are made of mud in which bundles of sponge spicules 

 are usually embedded, and are furnished externally with characteristic spine-like 

 processes. 



Remarks. Augener {loc. cit.) is not convinced that Mcintosh's mirabilis and Ehlers 's 

 spinifera are identical. I have examined the hooks of the first thoracic torus in one of 

 Mcintosh's type specimens and they show the characteristic long shaft and absence of 

 denticles above the main tooth. As Augener has pointed out, the main tooth is grooved 

 at the sides and these grooves are probably equivalent to normal denticles. 



In a specimen from WS 244 I noticed in the first thoracic torus a group of about six 

 hooks with a well-developed second tooth above the main fang. The remaining hooks of 

 the torus were of the typical unidentate form. This single second tooth is quite different 

 from the row of denticles figured by Fauvel (1927, fig. 92 e) for the hooks of the first 

 unciniger and I believe the P. mirabilis, Mcintosh of Fauvel, to be a distinct form. Apart 

 from this, the hooks of the second unciniger are not long shafted as Fauvel shows them. 



Subfamily THELEPINAE 



Tentacular lobes of prostomium not enlarged. Gills filiform and arranged in trans- 

 verse rows. Uncini in single rows throughout the body. 



Genus Thelepus, Leuckart 

 Dorsal bristles over a large number of segments. Branchiae two or three pairs, 

 simple, cirriform not arising from a common stalk. No lateral lobes in the anterior 



