1920.] E. Ghosh : Anatomy of the Solenidae. 65 



surface and traversed by numerous transverse bands of muscle. 

 No cruciform muscle. Siphonal tubes completely separate from 

 each other. A wide siphonal space posteriori}^ A very short 

 stout foot with a disc-like anterior end projecting forwards and 

 downwards. Retractor pedis anterior muscle bifurcated with the 

 bands passing upward and backward. Gills simple, homorhabdic 

 and non-plicate. Outer lamella of the outer gill attached dorsally 

 to the mantle lobe. Intestine of several long loops. Heart in 

 the middle of the pericardial chamber. Viscero-parietal ganglia 

 beneath the bifurcation of the retractor pedis posterior muscle. 



Novaculina gangetica, Benson. 

 (PI. Ill, lig. 20-23). 



1830. Novaculina, Benson, Glean. Science, Calcutta, II. 



1858. Subgen. Novactilina, Benson (Gen. Siliqnaria, Schumacher), 

 ^ Adams, Gen. Recent. Moll., II, p. 31.7. 



1874. Solecurtus novaculina, Bsnson sp.. Reeve, Conch. Icon., XIX, 

 fig. 31 a, b. 



1S87. Subgen. Novaculina (Gen. Solecurtus), Fischer, Man. Conch., 

 p. 1,107. 



1889. Tagelus gangeticus (pars), Benson sp., Clessin, Martini-Chem- 

 nitz, Condi. Cab., XI {Solenacea), p. Si. 



Animal. The body is about three times as long as broad, 

 widest in the vertical line of the antero-ventral notch. The an- 

 terior margin is nearly vertical with a deep notch at the antero- 

 ventral corner; it does not project bej^ond the anterior margin of 

 the shell. The pedal aperture is somewhat oblique and extends to 

 the antero-ventral corner. The dorsal margin is convex in front 

 and concave behind. The fused ventral margins form a wide sur- 

 face, in breadth about one-third the body length ; the surface is 

 slightly convex in front and concave behind. The siphons consist 

 of two separate anal and branchial tubes connected proximally 

 with the posterior margins of the mantle lobes through the inter- 

 vention of lateral flaps. The branchial siphon is longer and stouter 

 than the anal, being one-half to one-third the body length ; the 

 surface of both the siphons is finely ribbed, but not segmented. 

 The apertures are constricted and without tentacular fringe. A 

 circular space is formed round the base of the siphonal tubes and 

 enclosed by the mantle lobes and the lateral flaps from them. 

 This space, named the siphonal space, is mentioned by Weber (50, 

 p. 280) to extend halfway between the base of the upper siphonal 

 tube and the posterior adductor muscle. The siphons do not seem 

 to be completely retractile inside the shell. 



The anterior adductor muscle is elongated and obliquely 

 pyriform. The anterior limb of the retractor pedis anterior muscle 

 is placed behind the anterior adductor muscle. The posterior 

 adductor muscle is elongated with a notch on the postero-dorsal 

 aspect in which is lodged the retractor pedis posterior muscle. The 

 siphonal muscle is a thick sheet, elongated and trapezoidal in shape. 



The labial palps are shaped like an equilateral triangle, the 

 outer one extending slightly more ventralwise than the inner. A 



