108 
PACIFIC SCIENCE, VoL XV, January 1961 
FORMULA: The body form and general shape of the lateral fins is reminiscent of S. bipunctata 
Quoy et Gaimard 1827 and S. hispida Conant 1895. But the fact that the posterior and caudal fins 
of S. peruviana both are in such close proximity to the seminal vesicles distinguishes it from either 
of these two species. 
The seminal vesicles in the later stages of development resemble those of S. neglecta Aida 
1897 and S. friderici Ritter-Zahony 1911. Features that separate S. peruviana from S. neglecta and 
S. friderici are the robust body form, length of ovary, size of ova, shape of the lateral fins, and shape 
of the eye pigment. 
The fact that the new species has no intestinal diverticula separates it from both S. neglecta 
and S. hispida. 
Table 1 compares the features of the species discussed above. 
Sagitta popovicii n. sp. 
Fig. 3 A-F 
Holotype, 1 specimen, USNM no. 29923 
Paratype, 1 specimen, USNM no. 29924 
Body short, translucent, rigid; constriction at tail septum inconspicuous. Anterior fins start at 
posterior end of ventral ganglion, completely rayed, slightly tapered, widest near posterior end. 
Posterior fins separated from anterior fins by short but distinct interval, wider than anterior fins, 
widest posterior to septum, completely rayed, reach seminal vesicles. Caudal fin with rounded pos- 
terior margin, reaching seminal vesicle. Anterior teeth 3-4; posterior teeth 6-10; hooks 6-7. Sem- 
inal vesicle large, opaque, very conspicuous. Ovaries reach posterior region of anterior fins. Ova 
large, filling body cavity; up to 9 or 10 ova in a single row. Collarette present, small. Intestinal 
diverticula absent. Corona ciliata not observed. Pigmented area of eyes with an elongate extension 
arising from median side. 
The above description is from four specimens, three of which were in such condition that the 
armature formulae and measurements could be determined. All four specimens were fully mature. 
The one specimen for which the measurements and formula were not made was found preserved 
in a distorted position. 
FORMULA: 
BODY TAIL LENGTH 
LENGTH SEGMENT ANTERIOR POSTERIOR MATURITY OF OVARY 
IN MM. °/o TOTAL HOOKS TEETH TEETH STAGE IN MM. 
T8 32^8 7 3 6^7 IV LI 
5.9 (2 indiv.) 26.3-28.6 6-7 3-4 9-10 IV 1.1 
REMARKS: The present new species is similar in size and certain characteristics to S. bedfordii 
Doncaster 1903 (redescribed by Tokioka, 1942, and considered by him as synonymous with S. 
pseudoregularis, Tokioka, 1942 and 1952), S. sp. Tokioka 1954, and S. pseudoregularis Oye 
1918. The differences and similarities are readily compared in tabular form. Inspection of Table 
2 clearly illustrates that S. popovicii differs significantly enough from the other species to justify its 
designation as a new species. The name, Sagitta popovicii , is given in honor of Dr. Zacarias 
Popovici. 
REFERENCES 
Tokioka, T. 1942. Systematic studies of the plankton organisms occurring in Iwayama Bay, 
Palao, III. Chaetognaths from the Bay and adjacent waters. Palao Trop. Biol. Sta. 2(3): 
527-548. 
1952. Chaetognaths of the Indo-Pacific. Annot. Zool. Jap. 25(1-2): 307-316. 
Fig. 3. Sagitta popovicii n. sp. A, Entire animal, ventral view; B, eyes, showing pigment distribution; C, 
anterior teeth; D, posterior teeth; E-F, stages of development of seminal vesicle. 
