EVKS AND NEURAL GLANDS IN CVCLO3ALPA. 197 



The development of the eyes and neural glands has been de- 

 scribed by Metcalf for Cyclosalpa pinnata, chain and solitary forms. 



CYCLOSALPA DOLICHOSOMA-VJRGULA, chain form. 



The condition of the eye in this species is of interest because 

 it forms the third link in 'a series of three conditions bridging 

 over the gap between the Cyclosalpce and the true Salptc. The 

 structure of its neural glands is not unique. 



The brain of Cyclosalpa doliLJiosoina-virgnla is a ganglion of 

 almost spherical shape (Fig. i). Two outgrowths from the 

 ventral surface, one on either side of the mid-line, extend to the 

 neural glands whose position is ventro-lateral to the ganglion. 

 These glands, with their long lateral ducts, are partially shown 

 in Fig. i (/i, gland ; d, duct). On the postero- dorsal surface of 

 the ganglion is a slight protuberance (Fig. 5,//'). All the nerves, 

 with the exception of a single pair, spring from the equatorial 

 zone of the ganglion (Fig. i). One pair arises from the ventral 

 outgrowths. The nerves are probably constant in number for 

 the species forty-eight. 



The large ovoid eye (Fig. i) projects anteriorly from the pos- 

 terior end of the dorsal surface of the ganglion, and the long axis 

 of the eye makes with this surface an angle of about 30 (Fig. 5). 

 The eye points about 40 from the mid-line of the body, to the 

 right or left, according as the animal lies to the right or left in 

 the chain. One third of the eye, approximately, extends beyond 

 the anteriormost edge of the ganglion. 



There is a deep invagination of the ectoderm into the narrow 

 space between the eye and the ganglion, and a less abrupt invag- 

 ination just posterior to the ganglion (Fig. 5). In the ectodermal 

 chamber formed between these two invaginations lies the eye, 

 which presses closely against the ectoderm only at its tip. Blood 

 sinuses (Fig. i, bl] which surround the ganglion are continuous 

 with this optic chamber (Fig. 5, oc). 



The ganglion has the usual fibrous core, and a peripheral cellu- 

 lar layer (Fig. 5), which extends inward about one seventh of 

 the diameter. The postero-dorsal protuberance (Fig. 5, pr), is 

 made up of ordinary ganglionic cells. Large nerve cells (Fig. 

 5, nc], lie in the equatorial zone from which the nerves arise. 



