THE PELAGIC TUNIC AT A. 207 



10 mm.; maxiinnm width of tail ].7o 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 thiclv, 

 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 margin 

 of the tail, unoccupied by muscle. 



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

 broad, short process on its ventral side. 



Hijpi'physcul orr/aii 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 

 the apex. 



Gaiit/iioa considerably smaller than the hypophyseal organ, and apparently 

 connected with the apical end of the latter. Olocys/, witli its contained otolilh, 

 rather small and indistinct. 



Periphari/nffeal band broad, its dorsal limbs reaching far back behind the 

 ganglion and hypophyseal organ. 



En(lu!<t>/lc tj^pically very large and conspicuous, owing to the great develop- 

 ment of the four series of gland cells. 



Oesoj^hcigus curved to nearly a semicircle so as to enter the dorsal side of 

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

 rovmded-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 extending on forward in a nearly straight 

 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 compact mass. 



The " house," the [/ill openings and the iutegimienlarg glands alongside the 

 anterior end of the endo.style, we have not found, none of the specimens 



