392 CARL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. PHR0N1MID7E. 



PhroniiiieUa elongata. 



In 1885 Carus gave the following Latin diagnosis, translated from Claus: 



»Corpiis gracile; abdomen pedibus 3 natatoriis, 2 saltatoriis munitum; pedes thoracales 

 tenuissimi, debiles, et paris III. et magis IV. fere flagelliformes; pedes paris V. unguiferi, haud 

 chelati.» 



In 1887 I gave the following diagnosis of a variety of Phroniraella elongata, 

 under the narae Pli. filiformw. 



»Second pair of perajopoda miich longer than the first; metacarpal processes longer than 

 halt' the dactylus. Fourth pair longer than fifth. Femora of sixtli and seventh pairs eqiial in 

 length. Second pair of uropoda well developed.>' 



In the same j^ear Gilks described as a new species Phronimella hippocepliala, which, 

 however, in my opinion, is only a very young male of Ph. elongata. From his descrip- 

 tion the following passages may he quoted: 



»The head somewhat resembles that of a horse in shape, but the resemblance is not nearly 

 so striking as that of the first species (= Phronima bucephald) to the head of a bull. It is not 

 so broad at the top, and no fold surrounds it ; so that the appearance of a cephalic shield is not 



produced; its dorsal aspect is covered with a large, widely separated pair of apical eyes. 



The thorax is long, narrow, depressed rather than compressed, the first two dorsally visible seg- 

 ments scarcely separable. The third has the inferior angle of its pleuron produced into a sort 

 of triangulär spine, overlapping the second. The fourth and fifth, of nearly equal length, form 

 the widest portion of the body; the sixth longer and narrower than these; and the last, the longest 

 and narrowest of all, is provided behind with a spine on either side of the middle line and has 

 this posterior börder considerably everted, so as to admit of hyperextension of the abdomen on 

 the thorax.» 



In 1888 Stebbing gave exhaustive descriptions of several forms or varieties of 

 Phronimella elongata, so that, referring the reader to his work, I shall restrict myself 

 to give here only some details respecting the variety which I previously called Ph. filiforviis. 



The female. 



Pl. XVI, fig. 51—57. 



The body is very slender, with extremely elongated and almost filiform appendages. 

 The head and perteon together are quite as long as the pleon and urus together. The 

 integument is very thin and vitreous in appearance. 



The head is not tmce as deep as long. 



The eyes are smaller, and consist of fewer elements than in the larger and rnore 

 robust form of Phronimella elongata. 



The first pair of antennas (Pl. XVI, fig. 53) are fixed at the middle of the front 

 side of the head. The single peduncular joint is cylindrical, and is nearly twice as long 

 as broad. The single flagellar joint is very slender, cylindrical, four times as long as the 

 peduncle, and is furnished with six or eight long, olfactorj' hairs at the apex. 



The -perceon. The seventh segment is very narrow, and is somewhat longer than 

 the two preceding segments together. 



