Plate 2. 



Anelasma and Sacculina. 



h.c brood cavity. clt chitin. ch.pd chitin of peduncle, ch.pl chitinous plug of vas deferens. 

 en connective tissue sheath of testes, d hypertrophied germinal cells. d 2 Later stages in degeneration 

 of d. ec ectoderm, ep epithelium, gin germinal epithelium. I lumen of testis, lag lagena. lac lacunar 

 tissue, muse muscle, or ovary. ov.deg degenerate ova. pigm pigment, r root, s spermatozoa, sp sper- 

 matocytes, t testis, id vas deferens, vd.op opening of vas deferens, q* complemental males. 



Fig. 1. Section through a piece of ovary of Inachus scorpio, into which a root of Sacculina has penetrated. 



The root exhibits a lagena (lag) at its extremity. Degenerating ova (ov) are seen in the ovary. 



X 650. 

 Fig. 2. Optical section of a root-branch of Sacculina. X 50. 

 Fig. 3. Optical section of roots of Anelasma squalicola. The roots are shown springing from the surface of 



the peduncle (ck.pd), the chitin of the latter being pushed out to form the chitinous investment 



of the roots (eh). X 50. 

 Fig. 4. Part of a section through the peduncle of Anelasma squalicola, from the surface of which a root is 



seen to spring (r). In the interior of the peduncle the ovary is shown (ov), at the borders of 



which ova (ov.deg) are beginning to migrate into the lacunar tissue (lac). X 40. 

 Fig. 5. Section through a piece of the mantle of Anelasma squalicola showing the migrated ova (ov.deg) in 



process of degeneration. X 80. 

 Fig. 6. Transverse section through anterior region of testis of young Sacculina neglecta. X 865. 

 Fig. 7. Longitudinal section through the middle region of the testis of Peltogaster curvatus. X 435. 

 Fig. 7a. Spermatozoa of Peltogaster curvatus. X 865. 



Fig. S. Transverse section through posterior region of testis of young Sacculina neglecta. X 865. 

 Fig. 9. Transverse section through middle region of testis of Peltogaster curvatus. X 435. 

 Fig. 10. Transverse section through posterior region of testis of older Sacculina neglecta. x 865. 

 Fig. 11. Longitudinal section through the middle region of the testis of an old Peltogaster curvatus. X 435. 

 Fig. I la. Longitudinal section through wall of testis of old Peltogaster curvatus. X 435. 

 F'ig. 12. Transverse section through posterior region of testis of an adolescent Sacculina neglecta. X 435. 

 Fig. 13. Section through the vas deferens of Partkmopea subterranea. X 234. 

 Fig. 14. Transverse section through young Sacculina neglecta externa with complemental males (rf). X 93. 



