572 MATNARD M. METCALP, 



Section V. 

 The Anatomy of Octet cnenius patagoniensis^). 



Plate 40, Figs. 81—88. 



The family Octacnemidae includes the single genus Ocfacnemus, 

 of which but 2 specimens have hitherto been seen. These were collected 

 by the Challenger expedition and were studied by Moseley -) and by 

 Herdman "^). It is probable that these two specimens belong to the same 

 species. The United States Fish Commission steamer Albatross ob- 

 tained 15 very imperfect specimens of a probably distinct species of 

 the same genus, in 1050 fathoms of water, ofif Port Otway, Patagonia. 

 Through the kindness of Professor Brooks, this material was given 

 to me for study. I have already reported upon such features of the 

 anatomy of this form {Octacnemus patagoniensis) as can readily be 

 made out by dissection *). Upon examining sections of the animal to 

 determine more minute points of the anatomy, I find, unfortunately, 

 that the material is so poorly preserved that little can be discovered. 

 The character of the ganglion and neural gland is described in 

 Section I of this paper, page 549). The ahmentary canal is in a much 

 poorer state of preservation. The gonads are in fair condition. 

 However, as the animal is such an interesting one, the points that 

 can be made out are worthy of description. As a basis for the dis- 

 cussion of relationships I will describe the anatomy of Octacnemus 

 patagoniensis, quoting, in part, from my former paper. 



Octacnemus patagoniensis is hour-glass-shaped with the upper 

 end drawn out into eight blunt lobes (Fig. 81). The slit-like mouth 

 {mo) lies on the upper surface, near one edge, opposite an interval 

 between two of the eight lobes. The atrial aperture lies in the same 

 radius, but below the edge of the lobulated oral disc (Fig, 81 B cl.a). 

 The animal bears at the opposite end of the body a great number of 

 hair-like processes from the test (Fig. 81 A) similar to those by which 

 many of the simple Ascidians are attached to soft mud. Among the 

 fine hairy processes, in some of the individuals, are a number of 

 pieces of some calcareous substance, apparently an incrustation. This 



1) Cf. Metcalf, 1893 2. 



2) Moseley, 1876. 



3) Herdman, 1889. 



4) The specimens are poorly preserved and ai'e very soft, so that 

 dissection of the visceral mass is very difficult. 



