PLATE V 



CRUSTACEAN LARV.E (Pages 191, 102) 



The Roman imiuei'als indicate the appendages in their consecutive 

 order. 



/, 1st pair of appendages, or antennules. 

 //, 2d pair of appendages, or antennas. 



///, 3d pair of ajipendages, or mandibles. 



IV, V, etc., maxilliTe, maxillipeds, swimming feet, etc. 



od, unpaired eye ; oc, paired eyes ; lb, labrum. 



Figure 1. — Triurthrus Becki. A restoration of tlie ventral side of 

 the protaspis stage in accordance with tlie best evidence at present at- 

 tainable, as explained in the text. The F/th and the Vllih. pairs of ap- 

 pendages belong to the abdomen, which is marked off by a transverse 

 line; mt, metastoma; g, free-cheeks. 



Figure 2. — Apus cancrifonnis. (After Claus, from Faxon.) Phyllop- 

 oda. Nauplius larva, just hatched ; ventral side. Behind the mandibles 

 {HI) are indications of five tlioracic somites (>j). 



Figure 3. — Apus cancriformis. (After Claus, from Faxon.) Phyllop- 

 oda. Second larval stage (metanauplius) ; ventral side. The second 

 maxilla ( V) is wanting ; /", frontal sense organs. 



Figure 4. — Brancliipus stagnalis. (After Claus, from Packard.) 

 Phyllopoda. Nauplius stage. 



Figures. — Aiiemia c/mcilis. (After Packard.) Phyllopoda. Nau- 

 plius stage ; showing obscure segmentation. 



Figure 6. — Linmaida Hermanni. (After Lereboullet, from Packard.) 

 Phyllopoda. Nauplius; dorsal side; lirst pair of appendages obsoles- 

 cent ; labrum {lb) greatly developed. 



Figure 7. — Le/iidurus producius. (After Brauer, from Bernard.) 

 Phyllopoda. Nauplius with obscure segmentation of the trunk (//). 



Figure 8. — Leptodnrn hijalina. (After Sars, from Balfour and Bronn.) 

 Phyllopoda, Cladocera. Nauplius larva from winter egg ; y, rudimentaiy 

 feet. 



Figure 9. — Daphnia longispina. (After Dohi-n, from Claus.) Phyllop- 

 oda, Cladocera. Nauplius stage of embryo, with rudimentary append- 

 ages. 



Figure 10. — Mubinreclirostris. (After Grobben, from Faxon). Phyl- 

 lopoda, Cladocera. l'>mbryo from the summer egg in the nauplius stage, 

 developed in the brood-cavity of the parent ; appendages rudimentary. 



Figure 11.- — Cyclops tenuicornis. (After Claus, from Balfour.) Co- 

 pepoda, Natantia. Nauplius, first stage. This and the next are tlie 

 original forms described as Nauplius, by O. F. Miiller, and believed at 

 that time to be adult. 



Figure 12. — Cyclops tenuicornis. (After Claus, from Balfour.) Co- 

 pepoda, Natantia. Nauplius; second stage; iF, maxillae. 



