CEPHALOCHORDA 2 1 5 



preservation) was 65. Gunther's B. pelagicum had 67 ; while one specimen 

 described by Forster-Cooper (8) had 60. This specimen was 21 millims. long, 

 twice as long as Gunther's. 



There was no trace of oral cirri to be seen, nor did Forster-Cooper find any in his 

 specimen (8). This then appears to be a true character of the species, and not to be 

 due to any imperfection in preservation. It is, moreover, what might be expected. 

 The oral cirri probably have, as one of their functions, to direct currents of water into 

 the oral hood and so to the mouth and alimentary canal. This is absolutely necessary 

 in an animal which leads a sedentary life. But a pelagic form, by virtue of its mode 

 of life and motion through the water, would cause currents in the right direction, and 

 thus the oral cirri would be rendered unnecessary. 



No gonads could be observed in any of the six specimens. They were probably 

 immature. In none were the dorsal, ventral, or caudal fins preserved sufficiently well 

 to indicate, in any way, their shape and size. One specimen had traces of a caudal fin 

 which indicated that it was very well developed. 



On the whole, it may be said that in general shape, size, number of myotomes, 

 absence of oral cirri, large size of eye'-spot, and pigment spots on the nerve cord, our 

 specimens agree with Gunther's B. pelagicum, and it seems quite safe to refer them 

 to this species. 



Branchiostoma indicimi (Willey). Plate I., figs. 11-13. 

 Dolichorhynchus indicus, Willey, 1901. 



Two specimens, one from Galle (Stu. XXXVI. ), in 4f fathoms, and the other taken 

 oft* Watering Point (Stn. XXXVIII.) in the same locality, in 9 fathoms, I am 

 disposed to refer to this species, although the absence of some details in Willey's 

 description and the lack of figures render the identification a little uncertain. 



Both my specimens have long and well-marked preoral lobes, but the proportional 

 length of the lobes does not appear to be quite as great as in Willey's specimens 

 (fig. 11). Moreover, the preoral lobes of the Ceylon specimens do not appear bent as 

 Willey's figures show ; but it may well be that the bending was due to some 

 accident or injury, and that the lobes are not bent in life. 



One of our specimens measures 17 millims., and the other 36 millims. The latter 

 is a male, and has 29 right gonads and 25 left. The smaller one has no gonads and is 

 evidently immature. The larger one has a myotome formula of 43, 14, 13 total, 70 ; 

 while the smaller one has 41, 14, 14 total, 69. Both these formulae agree closely 

 with Willey's description. 



The dorsal fin is low and ends conterminously with the myotomes. Its outline in 

 the large specimens is interrupted by a peculiar wavy break (fig. 1 2), possibly due to 

 an injury and subsequent healing up. The notochord extends a long way in front ot 

 the dorsal fin. The nervous system is overlapped by the dorsal fin, while in Willey's 

 description the arrangement is the reverse of that. 



