408 



CRUSTACEA ENTOMOSTRACA. 



theirus Nordm., Anuretes Hell., Gloiopotes Stp. Ltk., Lutkenia Claus, 

 Nesippus Hell., Nogagus Leach, Demoleus Hell., Dysgamus Stp. Ltk., 

 Euryphorus Norclm., Trebius Kr., Elytrophora Gerst., Alebion Kr., Dine- 

 matura Latr., Echthrogaleus Stp. Ltk., Cecrops Leach, PhyUophorus Edw., 

 Gangliopus Gerst., Pandarus Leach, Laemargus Kr., Perissopus Stp. Ltk., 

 Lepidopus Dana., Caligeria Dana, Calistes Dana, Caligina Bened., Specil- 



ligus, Dana. 



Fam. 13. Dichelesthiidae. 

 Like the Caligidae, they are 

 generally external parasites at- 

 tached to the gills and soft parts 

 of the skin of fishes. They differ 

 from the Caligidae in the 

 greater reduction in size of the 

 swimming feet, the elongated 

 body and in the characters of 

 the antennae, the anterior being 

 many jointed and the posterior, 

 which are chelate or bear a hook, 

 being lengthened so as to pro- 

 ject beyond the margin of the 

 cephalothorax. M y tilicola 

 Steuer, M. intestinalis, internal 

 parasite in gtit of mussels in 

 Adriatic ; its blood is red. 

 Anthosoma Leach., Tucca Kr., 

 Norion Nordm. , Epachthes 

 Nordm., Lernanthropus Nordm., 

 with red blood ; Stalagmus 

 Xordm., Dichelesthium Herm., 

 D. stiiricnis on the gills of the 

 sturgeon. Lonchidium Gerst., 

 on the gills of sharks. Baculus 

 Lubb., probably a larval form of 

 a Lernaeid allied to Pennella. 

 Philichthys Stp., P. xiphiae. 

 The sexes differ markedly in the 

 adult state. The female in- 

 habits the mucous canals in 

 the head of the sword-fish 

 (Xiphias gladius), but the male 

 leads a free existence. Ler- 

 naeascus Claus, on soles. 

 Clavella Oken, Nemesis Roux, 

 Cycnus Edw., Pseudocycnus 

 Hell., Eudactylina Bened., Lam- 

 proglena Nordm. , D onus a 



Nordm., Aethon Kr., Ergasilina Bened., and (?) Polyclinophilus Hesse, 

 and Sabellacheres Sars. 



Fam. 14. Lernaeidae. Before they are fertilized the females (Fig. 

 2G6, b) resemble the males and conform to the type of the last two 

 families, having the anterior antennae short, the posterior hooked 

 and as in the last family projecting beyond the front margin of the 



FlO. 266. Lernaea branchialis. a male (about 

 2-3 mm. in length) ; 6 female at the stage in 

 which fertilization occurs (5-6 mm. in length) ; 

 e female in process of metamorphosis ; d the 

 same, with egg sacks formed (c and d natural 

 size). 



A' , A" the two pairs of antennae (the hooked 

 pair is the 2nd) ; D gut ; F', f' r the four 

 pairs of swimming feet ; G brain ; Go region 

 of the generative apertures ; M stomach ; 

 .l/.i7 maxilliped ; Oc eye; II suctnrial pro- 

 boscis ; S/> sack of spermatophores ; T testes ; 

 Vd points to the vasa deferentia on their way 

 from the testes to the genital (1st abdominal) 

 segment. (After Claus.) 



