642 Memoirs of the Indian Museum. [Vol. V, 



The type of this genus is Heteromastus filiformis (Clap.). It is known from the 

 Mediterranean, the west coast of France, and Belgium (Ostend), and from several 

 localities on the east coast of North America (Eisig, 1887, p. 839). The two forms 

 are apparently so closely related that it is difficult to distinguish them. The Chilka 

 Lake species is the smaller (55 mm. as against 100 mm.), but has more segments (212 

 against 140). The head, arrangement and structure of the setae, the branchiae and 

 tail are almost identical. Eisig' s figures of the branchiae (1887, Taf. 27, fig. 18) 

 shows a lobe on each side, between the dorsal and ventral lobes, which is absent in 

 the Chilka Lake specimens (fig. 23E). In H. filiformis the anterior abdominal seg- 

 ments are much longer than the thoracic segments, whereas in H. similis the lengths 

 do not differ. Moreover, though considerable work has been done in the intervening 

 area of the Red Sea and Persian Gulf, Heteromastus has not been found there. I 

 have not been able to examine specimens of H. filiformis, but it is probable that a 

 comparison of the two species would reveal other differences, whilst possibly reduc- 

 ing the importance of those mentioned above. 



Habitat. — This species was taken at three localities in the Chilka Lake, between 

 Nalbano and Berhampur, that is, near the inner end of the outer channel. Two of 

 these stations were worked in March and one in September. The specific gravity of 

 the water ranged from 1*000-1 0261. The species was taken once on the shore, 

 twice in a few feet of water. 



Genus Barantolla, gen. nov. 



Capitellidae having 12 thoracic segments, of which the ist is achaetous. Segments 

 2-7 have only capillary setae, segments 8-12 only elongate crochets. The abdominal 

 segments have short crochets only. The anterior thoracic segments have reticulate markings 

 on the skin, and the sculpture of the thoracic segments is rather elaborate. Branchiae in 

 the form of short finger-shaped lobes behind the dorsal setae of the middle and posterior 

 segments. These segments are provided each with a membranous collar, produced into 

 four shallow parapodial lobes. 



This genus shows marked affinities with Heteromastus and Mastobranchus, and it 

 is evident that the three genera are closely related. They all possess 12 thoracic 

 segments, of which the ist is achaetous. Barantolla agrees with Heteromastus in hav- 

 ing capillary setae on the anterior, long hooks on the posterior thoracic segments, and 

 only short hooks on the abdominal segments, but differs in having capillary setae on the 

 segments 2-7, whereas Heteromastus has them only on segments 2-6. Mastobran- 

 chus is peculiar in having capillary setae only, on the thoracic segments, and in the 

 dorsal bundles of a number of the anterior abdominal segments. On the other hand, 

 Barantolla agrees with Mastobranchus in having finger-shaped branchiae, situated 

 behind the dorsal setae of the middle and posterior segments. The parapodial lobes 

 (branchiae) of Heteromastus are very like those of Barantolla. Heteromastus and 

 Mastobranchus are peculiar in having finger-shaped appendages on the anal segment, 

 and it is unfortunate that no information is available on this point for Barantolla. 

 The general appearance of the abdominal segments is very similar in all three 





