Mr. F. S. Conant on the Chcetognaths. 213 



4. Sagitta hexaptera (d'Orbigny). 



From the same station as the precedin,£^ there are some 

 specimens, 24-34 millim. in length, which do not differ 

 enough from the 8. hexaptera of European writers to warrant 

 establishing a separate species. The caudal segment is one 

 fourth to one fifth the total length. Fins 5. Seizing-hooks 

 7-8. Anterior teeth 3-4. Posterior teeth 4-7. Ovaries 

 immature. The body-muscles are stouter than is stated for 

 hexaptera^ however, and the specimen sectioned sliowed two 

 large external diverticula from the intestine. It is very 

 possible that study of fresh material would show them to be a 

 distinct species instead of young hexaptera. 



5. Sagitta flaccida^ sp. n. 



This species was collected by Dr. Andrews at Bimini, in 

 the Bahamas. Length 13-18 millim. Breadth 1"25 millim. 

 Caudal segment about one sixth total length. Fins 5, the 

 middle and anterior comparatively short. Seizing-hooks 8 

 or 9. Anterior teeth 7 or 8, the inner very much longer than 

 the outer. Posterior teeth 10-12. Corona ciliata almost 

 wholly confined to the head, of an irregular oval outline. 

 Ovaries, containing well-advanced ova, short. No diverticula 

 from digestive tract. Caudal segment not divided longitu- 

 dinally by incomplete accessory septa, but showing an 

 arrangement of the testes and developing spermatozoa like 

 that figured by Grassi for S. hexaptera (Taf. ix. fig. 7). 

 Muscles of body slenderly developed, causing the preserved 

 specimens to have a very limp appearance. Epidermis but 

 slightly thickened around the neck, if any at all. 



Of the European forms, S. flaccida resembles hexaptera and 

 magna the most closely. It differs from them, however, in 

 being much smaller, in having a larger number of teeth, in 

 the smaller size of the caudal segment, and in the shape of 

 the corona. 



6. Sagitta tenuis^ sp. n. 



S. tenuis is a small species from Jamaica very closely 

 resembling S. hispida. I am indebted to Mr. C. P. Sigerfoos 

 for the specimens, which were collected by him in Kingston 

 harbour, June 1893. Maximum length 5"25 millim. Breadth 

 0*2 millim. Caudal segment about one fourth total length. 

 Seizing-hooks 7-8. Anterior teeth 4-5. Posterior teeth 

 7-10.' Shape of fins, of seizing-hooks, corona ciliata, acces- 

 sory longitudinal septa in caudal segment, number of tactile 



