io6 DISCOVERY REPORTS 



Morphology. Lateral commissural canals are, I think, always present. In S. turgida they are 

 sometimes absent. There are two inconstant characters about the commissural canals: (i) the position 

 on the dorsal radial canal from which they spring — sometimes opposite each other, but usually the 

 right-hand one given off before the left; (2) their course before junction with the lateral radial canals. 



Crodd 



Ccom 



C rod lot 



Crodd 



-Ccom 



Crodd 



Text-fig. 50. Sulculeolaria biloba. Basal parts of anterior nectophores taken by M.B.A. Plymouth in Celtic Sea, July 1937. 



A, dorsal view; B, D, lateral views; C, ventral view, x 8. 



The ventral side of these lateral radial canal-loops always springs from the pedicular canal-junction 

 (Text-fig. 50 C) of all four radial canals, and never from the ring canal as described by Bigelow & Sears 

 for a Mediterranean species (? S. turgida) which they called Galetta australis (1937, fig. 26 A). It is 

 not easy to see this junction in a lateral view. One side (left) of the base of the posterior nectophore 

 is higher than the other (Text-fig. 51 B). In consequence the cavity round the central boss of the base 

 of the anterior nectophore is asymmetrical, as can be seen in my Text-fig. 50 C. The width of the base 



