﻿PLATE XXXV. 



Order — Merostom ata . 

 Sub- Order — Xiphostjra. 



Anatomy of Limulus polyphemus, Latr. (after Owen). 



Fig. 



1. The nervous system, seen from the lower or ventral aspect. (Pp. 192 — 198.) 



A'. Inferior surface of cephalon. A". Posterior point of lateral or genal portion of 

 the cephalon. B'. Infero-lateral surface. B". Infero-median surface of 

 thoracetron (thoracico-abdominal shield), n xv. Nerve of anal segment. 

 (The other letters are the same as in PL XXXIV.) 



2. Compound eye and terminations of ocular nerve, from the dorsal aspect ; magnified 



6 diameters. (P. 192.) 

 d. Dorsal branch and divisions of ocular nerve, v. Ventral branch and divisions 

 of ocular nerve. 



3. Compound eye of a Trilobite (Phacops), magnified 3 diameters. 



4. Portion of the same compound eye, magnified 10 diameters. 



5. Entosternon and attached parts of muscles ; after vander Hoeven. (P. 187.) 



6. Chief parts of ovarium, oviducts, and opercular plate (upper or inner surface). 



(P. 208.) 

 m ll. Muscles of operculum. o,o. Oviducts, p. Oviducal outlets, q. Postero- 

 median lobe of ovary, q*. Antero-median lobe of ovary, q" '. Antero- 

 lateral loops and branches, q**. Postero-lateral cephalic branches, r, r. 

 Articular surfaces of opercular plate. 2. Second joint of opercular plate. 

 3. Third joint. 4. Median appendages of opercular plate. 



7. Section of terminal part of oviduct (after vander Hoeven). 



a. Oviduct, b. Anterior labium, c. Part of opercular plate. 



8. Portion of opercular plate with terminations of the sperm-ducts, p,p ; after van de 



Hoeven. (P. 209.) 



