44 DISCOVERY REPORTS 



Gonads. None of the zooids examined showed any trace of gonads, and no embryos or larvae were 

 found. 



Remarks. The characters of A. quadrisulcatum are given in Table 9 for comparison with those of 

 species from New Zealand and the Chatham Islands with which it is most likely to be confused. 

 These species all have a small number of folds on the stomach, but can be separated by other characters. 



Distribution. North end of North Island, New Zealand. 



Aplidium seeligeri sp.n. (Text-fig. 4, C, D, E) 



Holotype. St. 935. Size of colony 4 by 1-5 by 2-5 cm. 



Diagnosis of species. Colony consisting of a head of variable shape borne on a short stalk. Zooids 



irranged in small round systems with central common cloacal openings. Zooids with six-lobed oral 



iphon and a very short atrial siphon surmounted by a triangular languet with two lateral lobes ; ten 



.0 twelve equally spaced longitudinal muscles ; thirteen to sixteen rows of stigmata ; oesophagus quite 



long; stomach with nineteen to twenty-two folds. 



Occurrence. St. 935: North Island, New Zealand, 84m. St. 941 : North Island, New Zealand, 128 m. 



Colony (Text-fig. 4C, D). The larger of the two specimens (Text-fig. 4C) is a somewhat flattened 

 mass, 4 cm. long, 2-5 cm. across, and 1-5 cm. in height; the lower part is narrowed to form a short 

 tapering stalk apparently attached to the substratum by a small area. This specimen is buff-coloured 

 in the preserved state, smooth and soft, with the zooids showing through as brown spots. The 

 other colony (St. 941) (Text-fig. 4D) has an almost spherical head and a short stalk rather more 

 than half the diameter of the head. This specimen is 1-5 cm. in total length. The surface is smooth 

 and rather soft, and of a pale dirty buff colour through which the zooids can be faintly seen. In both 

 colonies the zooids are arranged in small round systems of six to twelve zooids, with a small central 

 cloacal opening. 



Zoom (Text-fig. 4E). In well-expanded zooids the thorax and abdomen each measures about 

 i-8 mm., and the post-abdomen up to 5 mm. 



Thorax. Six shallow lobes are present on the oral siphon, and the atrial opening (a.o.) is at the end 

 of a very short siphon opposite the 3rd and 4th row of stigmata. There is a short triangular atrial 

 languet with two small lateral lobes near the base. Ten to twelve slender longitudinal muscles are 

 equally spaced round the thorax and continue along the sides of the abdomen and post-abdomen 

 without appreciably converging in the post-abdomen. There are thirteen to sixteen rows of short oval 

 stigmata, with about twelve stigmata in each row. 



Gut. The oesophagus is more than twice as long as the stomach and narrows at both its upper and 

 lower ends. The stomach is barrel-shaped with nineteen to twenty-two narrow continuous folds. The 

 rectum is wide and ends in a simple anus at the level of the 10th row of stigmata. 



Gonads. The post-abdomen of some zooids contains a series of small testis follicles (t), with a straight 

 common sperm-duct. No ovary was present, but a few zooids had a single brown egg or developing 

 embryo in the atrial cavity. In these embryos the rudiment of the trunk measured 0-52 mm. in length. 



Remarks. A. seeligeri bears more resemblance to A. phortax (Michaelsen), a species also found in 



