THE PELAGIC TUNICATA. 207 



10 mm.; maximum width of tail 1.75 mm. Anterior two thirds of body 

 nearly cylindrical, posterior, visceral third considerably larger. 



Tail broadest a short distance behind its attachment and gradually 

 narrowing from here to its long, pointed extremity. Notochord rather thick, 

 though scarcely visible through the higlily developed musculature. Muscle 

 layer considerably broader on each side of the notochord than the notochord 

 itself, and leaving but a narrow band between its outer edge and the maro-in 

 of the tail, unoccupied by muscle. 



Branchial orifice very large, elliptical, regular in outline excepting for a 

 broad, short process on its ventral side. 



Hyprqjhyseal orgxin large, cone-shaped, the base of the cone directed ven- 

 trally and somewhat backward. Extremely long and strong cilia within the 

 duct, situated on some of the cells at the basal end, and extending up into 

 tlie apex. 



Ganglion considerably smaller than the hypophyseal organ, and apparently 

 connected with the apical end of the latter. Olocjsl, with its contained otolith, 

 rather small and indistinct. 



Peripharyngml band broad, its dorsal limbs reaching far back behind tlie 

 ganglion and hypophyseal organ. 



Endosti/le typically very large and conspicuous, owing to the great develop- 

 ment of the four series of gland cells. 



Oesophagus curved to nearly a semicircle so as to enter the dorsal side of 

 the stomach. Stomach large, left lobe much larger than tlie right, the former 

 rounded-quadrilateral in outline as seen from the left side, the antero-ventral 

 angle extended into a broad coecum which reaches down along the left side 

 of the rectum. Eight side scarcely developed into a true lobe. Intestine 

 arising from the right side, running forward, with a sharp bend toward the 

 median line near its middle, then extendintj; on forward in a nea^rlv straiifht 

 course to terminate close under the posterior end of the endostyle. Sexual 

 organs, situated on the postero-ventral side of the stomach, small in all the 

 specimens seen, hence not recognizably composed of male and female elements ; 

 apparently consisting of a single conipact mass. 



The "house," the gill openings and the integumcntnrg glands alongside the 

 anterior end of the endostyle, we have not found, none of the specimens 



