600 MAYNARD M. METCALF, 



Fig. 66. A horizontal section through the right side of the body 

 of Molgula manhattensis, showing the ovary and the testis and the 

 great involution of the epidermis, which serves in part to support the 

 oviduct. X 57 diameters. 



Plate 39. 



Reference letters. 



& small-celled ventro-lateral gauglion gl neural gland 



&' large-celled ventro-lateral ganglion i in Fig. 70 intermediate cells of 



J). G in Fig. 72 blood corpuscle the retina 



T). s blood-sinus lu lumen of the central nerve tube 



cl. ep cloacal epithelium n nerve 



d lateral duct of neui'al gland o. n in Fig. 79 optic nerve. 



d. I dorsal lamina p pigment of the eye. 



d. opening of a lateral duct of the ph. ep pharyngeal epithelium 



neural gland into the pharynx r. C rod cells of the eye. 



(or cloaca) ^ membrane between the optic 

 e eye chamber and the periganglionic 



ep epidermis blood-sinus. 



gg ganglion (brain) 



Figs. 67 — 69. Serial parasagittal sections through the intersiphonal 

 organs of Cyclosalpa pinnata, chain lorm. Fig. 67 is the more nearly 

 median of the three sections. X 1'*^ diameters. 



Fig. 70. A cross section through the intersiphonal organs of a 

 young Cyclosalpa pinnata, solitary form. X 1^5 diameters. 



Fig. 71. Part of a cross section through the intersiphonal organs 

 of an adult Cyclosalpa pinnata,, chain form. X 1^5 diameters. 



Fig. 72. A transverse section through the ganglion of a very 

 3^ouDg Cyclosalpa pinnata, chain form. X 200 diameters. 



Fig. 73. Part of a parasagittal section through the ganglion of a 

 young Cyclosalpa pinnata, chain form, showing the origin of one of 

 the lateral chambers of the neural gland. X ^^^ diameters. 



Fig. 74. Part of a parasagittal section through the ganglion of a 

 somewhat older chain individual of Cyclosalpa pinnata, showing a 

 later stage in the formation of one of the lateral chambers of the 

 neural gland with its duct. X 1^0 diameters. 



Fig. 75. A sagittal section through the ganglion of a young 

 embryo of Cyclosalpa pinnata, solitary form. X 1'^^ diameters. 



Fig. 76. A sagittal section through the ganglion of an older bud 

 of Cyclosalpa pinnata, chain form. X ^00 diameters. 



Fig. 77. Part of a parasagittal section through the intersiphonal 

 organs of Cyclosalpa chamissonis, chain form. X I'^O diameters. 



Fig. 78. A cross section through the intersiphonal organs of the 

 chain form of Salpa africana-maxima. X 1^^ diameters. 



Fig. 79. A cross section through the intersiphonal organs of Salpa 

 runcinata-fusiformis, solitary form. X ^^^ diameters. 



