XVI LIST OF ILLUSTRATIONS. 



Page. 

 Longitudinal section of thelycum of a mature Peneus hrasiliensis, Bhowing the 

 darkly stained sperm enveloped in a light secreted mass and enclosed by the 



scales {Sc) overlapping the shelf {S) 424 



Part of ventral side of thorax of Parapenseus constrictus, showing bases of legs, 



one of the first pleopods, and the scales (Sc) and shelf (S) of the thelyctim. . . 425 

 Longitudinal, lateral section of thelycum of Parapenseus constrictus, S, shelf, and 



Sc, scale; overhanging a branched cavity 42& 



Cross section of anterior part of thelycum of Parapenseus constrictus, showing the 



shelf {S) penetrated by lateral cavities right and left 426 



Cross section posterior to that shown in fig. 8 426 



Section across the middle of the thelycum, posterior to the sections shown in 



figs. 8 and 9, with the shelf {S) overarched by the scales {Sc) 427 



Surface view of under side of thorax of a female Polycheles sculptus, showing 

 bases of legs and large pair of spermatophores fused together and fastened to 



the shell between the last pairs of legs 429 



Cross section of ventral part of thorax of Polycheles sculptus with nerve cord 

 below and the applied spermatophores above outside the shell which is indi- 

 cated as a dark layer 430 



Cross section posterior to that shown in fig. 12 431 



Surface view of base of last thoractic leg of male Polycheles sculptus showing 

 below the deferent duct and contained sperm cut across and above the large 



dark spermatophore emerging from the orifice 432 



Cross section of base of last leg of male Polycheles sculptus, near the external 

 orifice of the deferent duct, showing the muscular wall of the duct as a dark 

 circle enclosing the clear spermatophore secretion and a central core of sperm . 433 



Glaucosoma burgeri 441 



Lutianus vitta 449 



Lutianus russelli 451 



Lutianus vaigiensis 458 



Pristipomoides sparus 461 



Pristipomoides sieboldii 463 



Aphareus furcatus 469 



Cranuim of Aphareus furcatus. als, alisphenoid; has, basisphenoid ; bo, basi- 

 occipital; e, ethmoid; eo, exoccipital; epo, epiotic; /r. frontal; opo, opis- 

 thotic; p, parietal; pas, parasphenoid; pf, prefrontal; pro, prootic; pto, 



pterotic; so, supraoccipital; spo, sphenotic; v, vomer 470 



Portion of the skull of Erpetosuchus hansensis Moodie. J/a;=maxilla, N= 



nasal. Lateral line canal represented by heavy broken line 492 



Outer surface of left mandible of Erpetosuchus hansensis. 4=angular, Ar= 

 articular. Operculo-mandibular lateral line canal represented by heavy 



broken line 492 



Inner surface of the mandible of Erpetosuchus hansensis Moodie. J.=angular, 



J.r=articular, Z)=dentary, Pa=prearticular, -S'=splenial 493 



Right ramus of mandible of Crocodilus. Ang=2kngVi\ax, J.rf=articular, D= 



dentary, <S'/)Z=splenial, <S'Mr=coronoid 493 



Genotypes of Stomatopora and Corynotrypa, illustrating generic differences. 



a, Stomatopora dichotoma. Jurassic, Hampton Cliffs, England, b, Cory- 

 notrypa delicatula. Upper Ordovician, Cincinnati, Ohio 499 



Characteristic species of Corynotrypa, X20, illustrating variation in stolon (s) 

 zooecium proper (z), and angle of divergence (g). a, Corynotrypa delicatula; 



b, C. abrupta; c, C. curta; d, C. injlata; e, C. turgida 500 



Corynotrypa delicatula section. Group of zooecia, X20, showing specific differ- 

 ences, a, Corynotrypa delicatula; b, C. barberi; c, C. elongata; d, C. nitida; 



e, C. tenuichorda 505 



