PLATE V 



CRUSTACEAN LARV^ (PAGES 191, 192) 



The Roman numerals indicate the appendages in their consecutive 

 order. 



/, 1st pair of appendages, or antennules. 

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



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



IV, F, etc., maxillae, maxillipeds, swimming feet, etc. 



ocl, unpaired eye ; oc, paired eyes ; Ib, labrurn. 



FIGURE 1. Triarthrus Becki. A restoration of the ventral side of 

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

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

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

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



FIGURE 2. Apus cancriformis. (After Claus, from Faxon.) Phyllop- 

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

 (III} are indications of five thoracic somites (y). 



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. Branchipus stagnalis. (After Claus, from Packard.) 

 Phyllopoda. Nauplius stage. 



FIGURES. Artemia yracilis. (After Packard.) Phyllopoda. Nau- 

 plius stage ; showing obscure segmentation. 



FIGURE 6. Limnaida Hermanni. (After Lereboullet, from Packard.) 

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

 cent ; labrum (Ib) greatly developed. 



FIGURE 7. Lepidurus productus. (After Brauer, from Bernard.) 

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



FIGURE 8. Leptodara hyalina. (After Sars, from Half our and Bronn.) 

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

 feet. 



FIGURE 9. Daplmia longhpina. (After Dohrn, from Claus.) Phyllop- 

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

 ages. 



FIGURE 10. Moina rectirostris . (After Grobben, from Faxon). Phyl- 

 lopoda, Cladocera. Embryo 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 the 

 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 ; IV, maxillae. 



