POLYZOA. Ill 



below the membrane of the zocecium, above the one to which they belong, are finely- 

 punctured and have a calcareous arch above the zocecial orifice. The colony is of a 

 brownish colour and adheres closely to the bivalve shell on which it is growing. 

 Locality : Gulf of Manaar. 



Siphonoporella bursaria (MacGillivkay, 23). 



The Ceylon colonies of this species have avicularia with spatulate mandibles, 

 interspersed here and there among the zocecia, on separate areas. In old specimens 

 the front wall of the zocecium is distinctly punctured. With these slight differences 

 the specimens have all the appearance of Membranipora rossellii (Aud.) which 

 MacGilliyray (23, plate xxvi., fig. 4) later named Amphiblestrum bursarium. 

 There is even an indication, in his drawing of one of the zocecia, of a siphon, which is 

 clearly present in the Ceylon specimens. I believe the specimens undoubtedly belong 

 to MacGillivray's species. 



Localities : Off Galle ; off Trincomalee ; and from the Gulf of Manaar (several 

 good colonies). 



Family : ONYCHOCELLID.E. 



Onychocella antiqua (Busk). 

 Locality : East Cheval Paar, Gulf of Manaar. 



Onychocella abyssicola (Smitt, 26). 

 Localities : Gulf of Manaar ; and off Galle at Station XL., 10 miles off Watering- 

 Point, 34 fathoms. 



Onychocella cucullata, n. sp. Plate, fig. 1. 



Zoarium incrusting or erect, branching and bilaminar. Zocecia large and irregularly 

 oval, raised towards the upper end, where the margin is often coarsely beaded. 

 Operculum large and horse-shoe shaped, bent forward along with the raised portion 

 of the zocecium. Cryptocyst coarsely granular and punctured on the front wall, 

 descending as in Steganoporella lateralis, MacGillivkay (24), to the basal wall of 

 the zocecium and pierced by a tubular orifice which has an everted rim. Avicularia 

 curved over the top of the zocecium, usually branched on one side and having the tips 

 of the branches more or less forked. A triangular swollen area, probably ocecial, is 

 seen above some zocecia, having an oval opening covered by a membranous operculum, 

 situated in the centre of the beaded upper margin of the zocecium to which it belongs. 



Localities : Gulf of Manaar ; and off Trincomalee. 



This species appears to be closely allied to Steganoporella in the form of zocecium, 

 but has a smaller operculum and avicularia of the Onychocella type. The two forms 

 present in this collection, incrusting and erect, have the same zocecial and avicularian 

 characters, and cannot therefore be separated. The erect form is represented by 



