244 



DISCOVERY REPORTS 



Stage IV (PI. XIII, fig. 4). The fully developed seminal vesicles persist into stage IV, the ovaries 

 swell and become longer, and the change from the thin rod-like ovary to the thick form marks the 

 beginning of this stage. The eggs are not round, owing to pressure against each other in the ovary, but 

 they are considerably larger than normal for stages II and III. It is easy to recognize this stage : in all 

 cases the ovary has reached a length more than 40% of the total body length, and no animal in stage III 

 has been found with the ovary in excess of this percentage, with the exception of the specimen marked 

 as 1 1 I/I V in Table 5 which has an ovary 44% of the total body length ; this was a contracted specimen 

 whose body length was probably several millimetres longer than is shown in the table. 



The seminal vesicles discharge during stage IV. The sperms are apparently spread throughout the 

 ovaries, and there is no conspicuous receptaculum seminis. The ovaries in living S. gazellae are con- 

 spicuous pale organs ; their lateral margins and the interstitial material are pale yellow or straw coloured. 



Table 6. A comparison of the head armature of specimens in stages II and V of maturity 



Stage V. Kramp did not find any 5. maxima at this stage, and presumed that they died after 

 spawning. There are several specimens in the Discovery collections which may be referred to this 

 stage, but they all appear to have been dead when caught. The eggs have been discharged, but the 

 position of the ovary is occupied by an irregular mass of material which is sometimes not confined to 

 the limits of the ovary but is spread throughout the body cavity and even extends down into the tail 

 segment. The tail septum is sometimes broken, possibly by damage in the net, but perhaps by the 

 effort of discharging the eggs, and the appearance of the animals in this state with opaque tail 

 segments is suggestive of stage II. Examination of the head armature, however, immediately demon- 

 strates the difference as is clear from Table 6. 



No animals have been found which can be presumed to have spawned and begun to regenerate their 

 gonads; nor does there seem to be a stage comparable with stage V in Eukrohnia hamata (usually 

 described as var. antarctica) which is frequently taken in the deeper nets, and sometimes in the shallow 

 ones. Evidently the spent S. gazellae die after spawning and sink below the range of the nets. 



SYNONYMY 



Sagitta gazellae Ritter-Zahony, 1909 



Sagitta hexaptera (part) Steinhaus, 1900. 

 S. hexaptera (part) Fowler, 1907. 

 Sagitta innom. Fowler, 1908. 



S. gazellae Ritter-Zahony, 1909. 



5. gazellae Ritter-Zahony, 191 1. 

 S. gazellae Germain, 1913. 

 S. gazellae Jameson, 1914. 

 S. lyra Johnston & Taylor, 1921. 

 S. gazellae Burfield, 1930. 



' y y Bollmann, 1934. 



S. gazellae \ yj ^ 



S. maxima group (part) Thiel, 1938. 



5. lyra (part) Thomson, 1947. 



