1354 THE VOYAGE OF H.M.S. CHALLENGER. 



Length, four-fifths of an inch. 



Locality. — April 26, 1876; off St. Vincent, Cape Verde Islands; lat. 16° 49' N, 

 long. 25° 14' W.; surface, night; surface temperature, 73°'2. One specimen, female. 



Remarks. — The specific name is derived from the Greek word /xeyaXdSous, meaning 

 with a large tooth, and refers to the unusually large tooth on the centre of the palm in 

 the third perseopods. 



Akin to the present species, and perhaps identical with it, are two specimens labelled 

 " Pacific, Api to Cape York, surface." 



In the female specimen the marsupial plates are only slightly developed, and as com- 

 pared with the Atlantic specimen just described, the fourth joint in the third perseopods is 

 more elongate, the front tooth much larger than that at the centre of the palm, the fifth joint 

 more stumpy, very much shorter than the fourth. The length more than half an inch. 



The male specimen accompanying this female is only a quarter of an inch long, and far 

 less than a quarter of the bulk of the female, so that it might have been regarded as a young 

 one, but on examination the antennas proved to be those of an adult, the upper with a long 

 thick first joint to the flagelluni, having a large bush of filaments, and the following joints 

 slender, the lower with numerous filiform joints ; in this specimen the fourth joint of the 

 third perseopods is distally as broad as its length, the front apical tooth not very long, 

 the palmar margin having no very deep cavity and at about the centre two separate nearly 

 equal teeth, not very large, inclined towards the hinge of the following joint ; the fifth 

 joint has a very slight bulge of its inner margin between the two teeth just mentioned, 

 and with the finger only just reaches the tip of the front tooth of the fourth joint. 



A specimen, female, from Station 227, March 27, 1875 ; between Papua and Japan ; 

 lat. 17° 29' N, long. 141° 21' E.; surface temperature, 79°"2, appears also to belong to this 

 form or species. 



In the Brit. Mus. Catal. Amph. Crust., pi. 51, fig. 2, a form is represented which 

 shows much resemblance to the present species, and which is there named Phronima 

 custos, Risso, although, as Mr. Spence Bate had not seen the typical specimens of that 

 species, he gives the name with some reserve. His figure does not in fact agree with 

 Risso's, which is here copied in the Note on Risso, 1816 (p. 97), and which is also 

 copied in Desmarest's Consid. gen. sur la classe des Crust., pi. 45, fig. 1, in Lucas' Hist. 

 Nat. des Crust., pi. 18, fig. 6, and in White's Popular Hist, of Brit. Crust., pi. xi. fig. 4, 

 but by all these authors named Phronima seclentaria, without reference to Risso. 



Phronima tenella, n. sp. (PI. CLXL, A.). 



Last segment of the peraeon not very elongate, longer than the first of the pleon ; 

 postero-lateral angles of the first three segments of the pleon scarcely produced, those of 

 the third segment forming an acute point. 



