EXPLANATION OF PLATES. 



Plate VI. 



Anatomy. 



Fig. I. Median longitudinal section of head and anterior thorax of L. cruciaia: c, cephalon; as, oesoph- 

 agus; s, stomach. FiG. 2. Eye of L. variabilis. Fig. 3. Dorsal view of head, and anterior thorax 

 of L. variabilis. Fig. 4. Head and neck of L. iortua from Black Creek, N. C, showing three com- 

 plete revolutions. Fig. 5. Cephalon and mouth parts of L. cruciata: an' and an", first and second 

 antenns; c, cephalon; lb, labium; mx' and mx", first and second maxillae; mxp, maxillipeds; 

 T, rostrum. Fig. 6. Anal lamina of L. cruciata. 



Plate VII. 



Internal morphology. 



Fig. 7. Median longitudinal section of head of L. crMcfaia; z'j, infraganglion; m, muscles; oe, oesophagus; 

 s, stomach; sg, supraganglion. FiG. 8. Section of skin: ky, hypodermis; il, inner layer; ol, outer 

 layer; pc, pore canal. Fig. 9. Head and anterior thorax of L. variabilis, showing e, the eye, and 

 s, the convolutions of the stomach. Fig. 10. Young female of L. variabilis, ventral view, showing 

 I* and P, fourth and fifth swimming legs; ov and od, ovary and oviduct; re, rectum. Fig. ii. 

 Fully grown female of same species, side view, lettering as before, and eg, cement gland. Fig. 

 12. Median longitudinal section of posterior body of L. cruciata, lettering as in fig. 11. Fig. 13. 

 Section through pregenital prominence of L. cruciata, showing inner layer divided into separate 

 cells, lettering as in fig. 8. 



Plate VIII. 



Internal morphology. 



Fig. 14. Reproductive organs of adult female of L. cruciata, lettering as in fig. 11. Fig. 15. Posterior 

 end of ovary enlarged, showing genital protoplasm (gp) and egg filaments (ef). Fig. 16. Anterior 

 end of same ovary, showing much enlarged egg filaments (ff) and the mature eggs (e) resulting 

 from them. Fig. 17. Section of cement gland of L. variabilis, showing an egg (e) just ready to 

 enter the glandular portion of the oviduct, and gland cells (gc). Fig. 18. Transverse section of 

 the glandular portion of another specimen. Fig. 19. Transverse section through the body of L. 

 cruciata, posterior to the ovaries: eg, cement gland; od, oviduct containing eggs; i, intestine. 

 Fig. 20. Section of a fully formed blastula, showing superficial cleavage. 



Plate IX. 



The nauplius and second and third copepodid larvce. 



Fig. 21. Second copepodid larva from gills of Lepisosteus platostomus. Fig. 22. Newly hatched nau- 

 plius, after Nordmann. Fig. 23. Third copepodid larva from gills of Stizostedion canadense. 

 Fig. 24. Mouth parts, ventral view, lettering as in fig. 5. Fig. 25-29. First, second, third, 

 foiuth, and fifth swimming legs. Fig. 30. Maxilliped. 



Plate X. 



Copepodid larva. 



Fig. 31. First copepodid larva from gills of Lepisosteus platostomus. FlG. 32. First antenna. Fig. 33. 

 Second antenna. Fig. 34, 35. First and second swimming legs. Fig. 36, 37. Male and female 

 fomth copepodid larviE from gills of Stizostedion canadense. Fig. 38. Ventral view of maxillae. 

 Fig. 39. Dorsal view of maxilla. Fig. 40. Maxilliped. 



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