VOL. 2, PT. 2.] 



APPENDIX. 



185 



oe.— 



^sim 



an. 



Fig. 142.— Apsteinia astmmeteica, soli- 

 tary form. Ventral view of the 

 oesophagus, stomach, and intes- 

 tines from an individual 18 mm. 

 long, showing adult character. 



of the upper lip. Muscle 5 of the upper lip is a branch of the inter- 

 mediate muscle. Muscle 1 of the upper lip lies at its incurved edge. 

 Posteriorly it is in contact with the dorsal retractor muscle and 

 functions with it, though the fibers of the two muscles are not 

 continuous. Muscles 2 and 3 of the upper lip are continuous, 

 respectively, with muscles 3 and 4 of 

 the lower lip and are not connected 

 with either oral retractor muscle. The 

 little blunt protuberance in figure 140, 

 in the angle between the intermediate 

 muscle and the fifth sphincter of the 

 upper lip, is not a muscle, but a blood 

 vessel. 



The atrial muscles (figs. 140 and 141) 

 form a graduated series, as in Apsteinia 

 punctata (figs. 49 and 52, pp. 72 and 

 74), and show a similar atrial retractor. 



Over body muscle IX, on each side, in the embryo, is a small, 

 very short epithelial tube with collapsed, but not open, end. It is 

 indicated by a question mark on figures 140 and 141. The function 

 of these structures is doubtful, but one suspects they may serve as 



aids in attaching the 

 embryo to its nurse. 

 These organs are not 

 present in our adult 

 specimens. The 

 much longer pos- 

 tero-lateral languets, 

 shown by Apstein in 

 the embryo of this 

 species which he fig- 

 ures (fig. 58, p. 78), 

 are probably the 

 same structure. 



The placenta and 

 eleoblast are in the 

 usual condition. 

 The gut in the em- 

 bryo forms an open 

 loop around the 

 intestinal gland. 

 In the adult the gut is more compact (fig. 142), really forming a 

 so-called intestinal nucleus, though the elongated character of the 

 stomach makes this "nucleus" less spherical than in the true 

 Salpae. 



B. 



Fig. 143.— Apstenia asymmetrica. Dorsal views: A of the cili- 

 ated FUNNEL AND ANTERIOR END OF THE GILL OF AN ADULT SOLI- 

 TARY INDIVIDUAL X 50 DIAMETERS; B OF THE CILIATED FUNNEL OF AN 

 ADULT AGGREGATED ZOOID. 



