62 DISCOVERY REPORTS 



Gut. This agrees well with Michaelsen's account, except that in the ' Discovery ' material the anus 

 (a) is rather farther forward, and lies opposite the 3rd row of stigmata instead of the 4th. 



Gonads. There is no trace of gonads in any of the specimens. 



Remarks. Five species of Leptoclinid.es have been described from New Zealand and Chatham 

 Islands: L. diemenensis Michaelsen, L. sparsus Michaelsen, L. sluiteri Brewin, L. marmoreus Brewin, 

 and L. auranticus Brewin. L. sparsus is similar to L. diemenensis from which it differs in having stellate 

 pigment cells in the test. The characters which separate the remaining species are given in Table 18. 

 Some of these characters are not very satisfactory for distinguishing the species, but as the variation 

 within each species is not known at present, it is best to maintain them. 



Sluiter (1909) has described, under the name Polysyncraton, a number of species from the Indo- 

 nesian region evidently belonging to Leptoclinides. It is a little doubtful if these are all different species, 

 and I should not be surprised if a proper revision of the group, as represented in Australasian waters, 

 showed that the same species has been described under several names. This view is also expressed by 

 Tokioka (1949) in dealing with L. rufus (Sluiter) from Japanese waters. 



Distribution. North of North Island, New Zealand. 



Genus Trididemnum Delia Valle, 1881 

 Trididemnum auriculatum Michaelsen (Text-fig. 14) 

 Trididemnum auriculatum Michaelsen, 1919, p. 38, text-fig. 3. 



Occurrence. St. WS 84 : Falkland Islands, 75-74 m. 



Colony. The specimen is a large sheeting colony, varying from 2 to 4 mm. in thickness, of a dirty 

 white colour. Two or three common cloacal openings are visible on the surface. Regular stellate 

 spicules are densely packed in all layers of the test, and range from 37 to 66 n in diameter. 



Zoom (Text-fig. 14A). The zooid agrees closely with the description given by Michaelsen (1919), 

 except that the ' Discovery ' specimen has about seven spiral turns of the sperm duct, (s.d.), instead of 

 only five in the type specimen. The lateral thoracic organs are large and conspicuous, as in Michaelsen's 

 material. 



Larva (Text-fig. 14B). The larva is of the usual didemnid type, with three vertically arranged 

 papillae (p.) and four pairs of anterior ampullae (amp.). Both ocellus and otolith are present. The 

 larvae measure from 0-5 to o-6 mm. in length from the end of the papillae to the base of the tail. 



Remarks. Van Name (1945) suggested that perhaps this species was not distinct from T. pro- 

 pinquum (Herdman), but Arnback (1929) stated that a comparison of the species 'shows at once that 

 they are not identical'. The distinguishing characters particularly mentioned by Arnback are given in 

 Table 19. 



