REPORT ON THE SCHIZOPODA. • 89 



quite smooth. Moreover, two pairs of small dorsal denticles occur on the posterior half 

 of the telson. 



The uropoda (see fig. 11) are much shorter than the telson, and have the terminal 

 plates uniform in length. 



Habitat. — This species was obtained on November 18, 1875, in the South Pacific, oft" 

 the coast of Chili, where a few specimens were taken at the surface of the sea. 



21. Euphausia gracilis, Dana (PL XV. figs. 12-23). 



Euphausia gracilis, Dana, United States Exploring Expedition, vol. xiii., Crustacea, p. 644, pi. xlii. 



figs. 6, a~c. 

 Euphaiisla gracilis, G. O. Sars, Preliminary Notices on the Challenger SchizopoJa, No. 20. 



Specific Characters. — Form of body very slender and elongate. Carapace with a 

 single lateral denticle about the middle of the inferior margin ; anterior part very 

 slightly keeled above ; rostral projection sharply pointed. Caudal segments smooth 

 above, with very small rounded epimera. Last segment rather elongate ; preanal 

 spine simple. Eyes remarkably small, with the cornea scarcely at aU expanded. 

 Antennular peduncle without any dorsal lappet, basal joint shorter than the other two 

 taken together. Antennal scale oblong-ovate, apex obtusely truncate, outer corner 

 unarmed. Gills rather simple in structure, with but few digitiform lobules. Telson 

 with two pairs of dorsal denticles ; subapical spines smooth. Inner plate of uropoda 

 much longer than outer, and reaching the tip of the telson. Length aliout 1 mm. 



Remarks. — This form is without doubt the Euphausia gracilis of Dana, and in every 

 way entitled to its specific designation, being by far the most slender sjsecies of the 

 genus. Moreover, the animal can be recognised by its remarkably small eyes. 



Description. — The length would not seem to exceed 10 mm., and accordingly 

 the present species must take rank among the smallest belonging to this family. 



The form of the body (see PI. XV. fig. 1 2) appears exceedingly slender ; the tail in 

 particular is very elongate, attaining, as it does, more than twice the length of the 

 anterior division. 



The carapace is rather narrow, and exhibits on either side a single lateral denticle, 

 placed about the middle of the inferior margin, or, more precisely, just above the point 

 of insertion of the second pair of legs. Its anterior part is very slightly keeled 

 above, and juts out as an acutely pointed rostral projection, reaching considerablj' 

 beyond the ocular segment. 



The caudal segments are quite smooth above, and have the epimera very small 

 and rounded, but slightly projecting beneath the ventral face. The last segment is 

 very elongate and compressed, even a trifle longer than the two preceding segments 



(ZOOL. CHALL. EXP. PART XXXVII. 1885.) Oo 12 



