and on the Maininaria Manliattensis. 89 



sages tlirough the cloaca, and developed outside of the parent 

 animal. 



Tlie viscid fluid containing the ova deposited at the base of 

 the tubes, of a light orange-color, had assumed, in passing 

 through the cloaca, a threadlike appearance, irregularly folded 

 and glued together, as represented. On the following day 

 it had lost its folded appearance, and resembled the ex- 

 ternal envelope, " couche tegumentaire commune ; " (Milne 

 Edwards.) This substance, which appeared at first whitish 

 when the sun was shining upon it, is, as has been already men- 

 tioned, of a pale orange-color, which is caused by the yellowish 

 color of the yolk of the mature ova. The vesicular, or cellu- 

 lar bodies embedded in the hyaline gelatinous layer — the future 

 muscular sac, or mantle — are colorless ; they are green wnth 

 the PhallusicB according to Krohn, 1. c, and yellow with the 

 Ascidia infestiiialis, according to A. Kowalevsky.* 



The viscid mass had become tough, and its color had chano;ed 

 to ashy gray on the following day ; the next day it w^as con- 

 tractile ; the ova became visible with the naked eye. They 

 were round and of different sizes. After two or three days the 

 largest protruded somewhat above the surface of the common 

 envelope, and presented a circular or oval aggregation, like that 

 of the Mammarice found a year ago. The external envelope of 

 the ova had assumed the characteristics of the mantle. The 

 pigment had much increased. After an interval of four or five 

 days, on the eleventh day after the ova were ejected, I found 

 ova still of a round form, increased in size, with a central round 

 or oval orifice through which the motion of the cilise of the 

 branchial meshes were visible. The large orifice, without a tube, 

 led directly into the branchial sac, which formed a greater por- 

 tion of the body of these evidently young Mammarioe than in 

 those found during the previous year, with terminal openings, 

 and I found, at this stage of development, the embryo within 



* Entwicklungsgeschichte der einfachen Ascidien. Memoires de TAcadem. 

 des Sc. de St. Petersbourg ; vii. Serie, torn, x., No. 15, 1866. 



