268 



ENTEROPNEUSTA FROM THE SOUTH PACIFIC, 



Family. SPENGELIDAE. 

 Genus. Spengelia. 



4. Spengelia porosa Willey. 



A. Willey. Spengelia ; a new Genus of Enteropneusta. Q. J. M. S. Vol. XL. 1898, 

 p. 623. 



Colour, Measurements and External Form. 



Proboscis, rich yellow ; collar, bright orange ; body, dull yellow. The distinctive 

 feature in regard to the colour of this species is the bright orange of the collar. 



The length of the proboscis, in the fresh condition, greatly exceeds that of the 

 collar. During extension it measured up to 10 5 mm. in length ; the collar under the 

 same conditions measured 6"25 mm. After preservation the proboscis contracted to 

 5"25 mm. and the collar to 4 mm. 



The general shape of the body is subcylindrical and the body-wall is stout and 



firm. 



In the branchial region the body is quite cylindrical and faintly annulated. The 

 diameter of the body, in this region, alike in the vertical and transverse directions, 

 measures 5 mm. The gill-area, i.e., the dorsal tract bounded by the branchial grooves, 

 is long and band-like, measuring, in the living animal 30 mm. in length. The gill- 

 pores are visible externally in each branchial groove (PI. XXVII. Fig. 8). 



Only twenty millimetres of the postbranchial genital region were present in the 

 single available specimen, the posterior half of the body being lost. 



The genital region is characterised on its dorsal side by the presence of a double 

 series of very extraordinary dermal pits which dip down into the body for a relatively 

 great depth. They may be defined as specia.1 intergonadial depressions of the inter- 

 annular grooves of the body-wall. The mouth of each pit measures about 1 mm. in 

 diameter, and the pits taper towards their internal extremities which, except in the 

 case of the most anterior pits, end blindly near the wall of the gut (Text-fig. 3). 



PROBOSCIS. 



All that need be noted here about the musculature of the proboscis is that the 

 longitudinal muscles are not disposed in radial bundles as they are in the Ptycho- 

 deridae, and that the circular muscles are strongly developed. 



