CHAETOGNATHA. 213 
end of the tail fin. Corona ciliata entirely on the head; pear-shaped, with the narrow end 
lying just behind the brain, in front of the eyes. Hooks 8—10; anterior teeth small, 
about 10; posterior larger, pointed, varying from 12 to 16. 
This species is intermediate between S. heaaptera and enflata in size and in the form 
of the ovaries, and it differs from both in the larger number of teeth. Although it is 
closely connected with these two species, yet the differences are so constant that there can 
be no doubt of its distinctness. 
11. Sagitta pulchra nov. sp. (Plate XIII, figs. 4.4, 4B.) 
A moderate number of this species occurred both in the winter and spring collections. 
Its length is 2cm., of which the tail segment makes up one-sixth. The body is slender, 
with a thin body-wall, so that this species is intermediate between the large, inflated, and the 
smaller muscular types of Sagitta. The head is small, and the epidermis somewhat thickened 
behind the head. ‘The anterior fin begins at the abdominal ganglion, and is rather long, 
so as to be separated by a short distance only from the posterior. The front half of the 
anterior fin is very narrow and has no rays; the posterior part is rather wide. The posterior 
fin is like the anterior in shape, but the part without rays is shorter and that with rays 
wider. The rays do not extend quite to the base. 
The ovaries are rather long and slender, the vesiculae seminales small. The whole of 
the tail coelom is filled with developing spermatozoa. The corona ciliata is moderately long ; 
it begins in front of the eyes and rather more than two-thirds of its length is on the 
trunk; it is narrow and its sides parallel. Hooks 6, rather curved and slender; anterior 
teeth about 6, posterior about 10. 
This species is of interest in combining the characters of two groups of Sagitta, viz. 
the larger species, which have a thin body-wall, short corona and in which only part of 
the tail coelom is filled with developing sperm; and secondly the smaller species with thick 
body-wall, long corona and tail full of sperm-morulae, 
12. Sagitta polyodon nov. sp. (Plate XIII, figs. 3 A, 3 B.) 
Found in fair abundance in both winter and spring. 
This species is superficially very like S. serratodentata. Its length is about 12 cm., the 
tail one-fourth of the whole. The shape is that of serratodentata. The fin-rays spring from 
the base of the fins. The ovaries are long, extending to the anterior fins. The vesiculae 
seminales are rather large and projecting. The hooks are 6—7, with no serrations; anterior 
teeth 9—10, posterior 26; they are slender, truncated at the end, with small processes. The 
corona ciliata is long and rather wider just behind the neck than elsewhere. 
This species is distinguished at once by the great number of its teeth, which are 
more numerous than in any other known species. -It resembles Béraneck’s description of 
S. bedoti* in many ways, but differs in having a corona, in the length of the ovaries, 
and the greater number of teeth. Since Béraneck described S. bedoti from preserved 
specimens, in which the corona is often destroyed im one species while well-preserved in 
1K. Béraneck, ‘‘ Chétognathes de la baie d’Amboine,” Rev. Zool. Suisse, Vol. m1. p. 147, 1895. 
