210 LEONARD DONCASTER. 
I. LIST OF THE SPECIES. 
I. Genus Sagitta Slabber. 
1. Sagitta enflata Grassi. 
Strodtmann, Archiv Naturgeschichte, Jahrg. 58, Bd. 1. p. 348, 1892. 
This species is very abundant both im winter and in April, making up perhaps fifty 
per cent. of each collection. It agrees with Grassi’s description in most points; the tail 
segment is however rather shorter in proportion to the trunk, and the teeth are sometimes 
more numerous. Exactly the same differences are described by Aida (Annot. Zool. Jap. 
Vol. 1. p. 18, 1897) between the S. enflata found in Japan and those of European waters. 
This species has been hitherto recorded from the Mediterranean, Madeira and Japan. 
2. Sagitta magna Langerhans. 
Strodtmann, Archiv Naturgeschichte, Jahrg. 58, Bd. 1. p. 343, 1892. 
Fairly abundant in the winter, but not found in April. Only a few specimens reached 
a length of 3cm. Did not differ im any points from Grassi’s and Strodtmann’s descriptions. 
Recorded hitherto from Madeira and the Mediterranean. 
3. Sagitta tricuspidata Kent. 
Strodtmann, Archiv Naturgeschichte, Jahrg. 58, Bd. 1. p. 342, 1892. 
A rather scarce species in the winter, and not found in April. It is the largest species 
found, some specimens attaiming a length of nearly 4cm., In shape it is lke S. magna, 
but slightly narrower, and while the posterior fins of magna are nearly semicircular, those 
of tricuspidata are broader near their posterior ends, The ovaries are long and _ slender, 
and may extend to the front end of the anterior fins; the longest observed were 1°5 cm. 
in length. Hooks 4—8, anterior teeth 3, posterior 1; but in several specimens, making up 
a large proportion of the whole number, there were 2 anterior and either 2 or 4 posterior 
teeth. The posterior teeth are attached to a cuticular bar which bears a number of 
rounded projections. Such projections are commonly found in other Sagittas, corresponding 
in number and position with the teeth, and are in some cases sharply pointed, and in this 
species, although the teeth are reduced to very few, the projections remain, but are rounded 
off. A similar condition exists in S. magna. The corona ciliata is short, on the head 
and neck. 
This species has very few distinguishing characters; it is separated from magna chiefly 
by the absence of the very long moveable teeth in the anterior row, and from hexaptera 
by the small number of posterior teeth, but when the latter are as numerous as four, it 
becomes difficult to separate them with certainty. The teeth seem to have been reduced, 
and are at present very variable, but the typical number for the species is three anterior 
and one posterior. 
Recorded from the Pacific, the Atlantic, the Mediterranean and the Indian Ocean. 
