CHAETOGNATHA. 211 
4, Sagitta serratodentata Krohn. 
Strodtmann, Archiv Naturgeschichte, Jahrg. 58, Bd. 1. p. 347, 1892. 
A moderately common species both in winter and spring. Some specimens had as many 
as 18—20 posterior teeth and 10 anterior, instead of 12 and 8 respectively as are normal 
in European waters. 
Hitherto recorded from the Mediterranean, the Atlantic, and Japan. 
5. Sagitta hispida Conant. 
F. S. Conant, Johns Hopkins Univ. Circ. Vol. xtv. p. 77, 1896, and xv. p. 82, 1896. 
This species was rather scarce in the material collected in the winter, but in that 
obtained in April it was very abundant. It is characterized by the thickness and solidity 
of the body-wall, the thickened ectoderm behind the head, the intestinal diverticula in the 
neck, and the great number of tactile prominences. The teeth in the specimens from the 
Maldives were sometimes more numerous. than in Conant’s description; Aida mentions the 
same fact in specimens from Japan. Corona ciliata long and waved; in one specimen I 
found it divided into two parts, an anterior and a posterior. 
Described previously from the Atlantic coast of America, the West Indies, and Japan. 
6. Sagitta regularis Aida. (Plate XIII, fig. 7.) 
T, Aida, Annot. Zool. Jap. Vol. 1. p. 17, 1897. 
Occurred in small numbers in the winter. This species is very small, rarely more than 
5mm. The tail is one-third of the length of the whole. The fins are narrow, semi- 
elliptical, and have rays extending to the base. The tail fin and the posterior lateral 
fin both touch the vesiculae seminales, which are small. The ovaries extend to the 
anterior paired fins. The epidermis is thickened through the whole length of the animal, 
but very much so behind the head, so that there is no neck. The number of tactile 
prominences is very large, and they are arranged: with great regularity. The intestine has 
diverticula at its beginning. Hooks 7, anterior teeth about 4, posterior about 6. Corona 
ciliata rather long, waved, with a constriction in the middle. It is shorter than that of 
S. hispida, and lies entirely on the trunk. 
Hitherto recorded only from Japan. 
7. Sagitta flaccida Conant. 
F. S. Conant, Johns Hopkins Univ. Cire. Vol. Xv. p. 82, 1896. 
Only one specimen of this species was found, and it occurred in the collection made 
in April. The species resembles S. enflata very closely, but differs in the form of the 
teeth. There are seven or eight anterior and 10—12 posterior teeth, and they are longer 
and more slender than in enflata, and the imner ones, especially of the anterior row, are 
much longer than the outer. 
Described only from the Bahamas. 
