334 CAKL BOVALLIUS, AMPIIIPODA HYPERIIDEA. I. 2. PHRONIMIDiE. 



Dairella califovnica. 



The f e m a I e. 



Fig. 21—33. 



The l)ody is tolerably broatl, not at all coinpressecl, but is scarcely more thaii twice 

 as long as the pleon. The surface of the segments is uneven, fonning irregular tubercles 

 and furrows. The head and perceon togethei' are much longer than the pleon, the urus 

 and the last paix' of uropoda together. 



The head is irregulai-ly globular, inflated, and rises considerably above the dorsal 

 line of the perajon; it is nearly as broad as long, and is only a little deeper than long. 

 There exists no proper antennal groove but the antennas are fixed dii'ectly on the smooth 

 surface of the front side of the head. 



The eyes are divided into four portions, a top-portion and an inferior portion on 

 either side just as in Phronima^); the top-poi-tion is much larger than the inferior and 

 is separated from that in the other half of the head by a tolerably broad strip on the 

 crown of the head. 



The jirst pair of antennce (Pl. XV, fig. 22) are considerably more than half as long 

 as the head. The first jpint of the peduncle is somewhat longer than the two following 

 joints together; the third joint is longer than the second. The single flagellar joint is 

 finger-like, twice as long as the whole peduncle, and is fringed with comparatively short 

 olfactory hairs on the inner side. 



Of a second pair of antennas there is not the slightest trace. 



The mouth-organs are closely like those in Dairella latissima, and will be described 

 under this latter species. 



The i:)er(Bon is broad, rather depressed than compressed, resembling more the com- 

 raon form in Isopoda than that usually occurring in the Amphipoda; the form of the 

 person approaches that in Eutliamveus and also that in Scina (=^ Tyr o), but is not ca- 

 rinated as in this latter genus. The first and second segments are completely coalesced, 

 only the lowest parts, the epimerals, being free. Along the front margin of the first seg- 

 ment there is a duplicature of the integument, probably serving for the articulation of the 

 head. The third segment is shorter than the first two together, and equal to the fourth; 

 the fifth and sixth are a little longer; the seventh is as long as the third. 



The epimerals are firmly coalesced with the corresponding segments, but their upper 

 limit is marked by a ridge which runs along the under margin of the perason. 



The branchial vesicles are bottle-shaped, and are attached to the second and four 

 following pairs of peragopoda; those of the second, third, and sixth pairs are not half as 

 long as the coiTesponding femora; those of the fourth and fifth pairs are somewhat more 

 than half as long as the femora. 



The ovitecirices are much broader and longer than the bi'anchial vesicles, broad, 

 and feebly rounded at the apex. 



') Compare C. Claus, »Der Organismus der Phronimiden», Arb. Zool. lust. der Universität Wien. Tom. 

 2, p. 124 — 133 (66 — 75). The »Top-portion» of the eye corresponds with »das Scheitelauge», in Claus's treatise. 



