1920.] E. Ghosh : Anatomy of the Solenidae. 71 



Gen. Tagelus, Gray. 



181 7. Siliqitaria, Schumacher, Essai Noitv. Syst. Habit, des Vers Tes- 



tace, pp. 43, 129, pi vii, figs. 2. 3. 

 1851. MacJia, Gray, Cat. Brit. Mas., VII, p 61. 

 1854. Tagelus, Gray, Ann. Mag. Nat. Hist. (2) XIV, p. 24. 

 1858. Siliqiiaria, S(?hum., Adams, Gen. Recent Moll., II, p. 347. 

 1887. .Subg-en. Tagelus, Gray, Fischer, Man. Conch., p. 1107. 

 i88g. Tagelus, Gray, Clessin, Martini-Chemnitz, Conch., Cab., XI 



(^Solenacea), p. 68. 



The anatomy of three species of Tagelus, Gray (T. rufus, 

 Spengler, T. gibbus, Spengler, and T. divisus, Spengler) has been 

 described by Bloomer (lo^ 15) in full detail. His researches clearh' 

 point out that the two former species are closely related to each 

 other but differ a good deal from the last one {T. divisus), which is 

 somewhat related to Solecurtellus. A separate subgenus (Subtagelus) 

 is suggested for this species in the present paper. 



Animal. Bod}' somewhat elongated and rounded anteriorly. 

 Pedal aperture very long and wide, extending from the antero-dorsal 

 aspect of the anterior adductor muscle, through the anterior 

 margin, to the posterior end of the ventral margin in a vertical 

 line with the posterior adductor muscle. Ventral margins of the 

 mantle lobes united at a single spot with the cruciform muscle 

 placed in it. Cruciform muscle typically cross-shaped with the 

 posterior or both pairs of the limbs short. The mantle lobes are 

 free at their posterior margins from the point of concrescence to 

 the posterior end of the posterior adductor muscle. Siphon consist- 

 ing of two long separate anal and branchial tubes. Siphonal 

 space separated from the general pallia] chamber b}^ two lateral 

 processes extending from the posterior margins of the mantle lobes 

 to the proximal end of the siphon. Retractor siphonis muscle 

 well-developed. Anterior adductor muscle unequally divided into 

 two portions. .Po.sterior adductor muscle irregularly oval or tri- 

 angular, and united posteriorly with the mantle lobes and the 

 proximal portion of the siphon. Retractor pedis posterior muscle 

 connected with the posterior adductor muscle by its long bifur- 

 cated portions. Foot large, comparatively short and very deep. 

 Retractor pedis anterior fibres passing inside the longitudinal 

 muscles. Gills united dorsally at their margins beyond the foot. 

 Anterior lip beneath the posterior division of the anterior adductor 

 muscle. Pjdoric stomach produced posteriorly beyond the origin of 

 the coecum. Coecum of the crystalline style long, wide and pro- 

 duced forward and upward in a curved course to the dorsal aspect 

 of the visceral. Limb of the intestine forming closeh' placed folds 

 above. Viscero-parietal ganglia placed underneath the bifurcation 

 of the retractor pedis posterior muscle. 



The anatomical study of the genus b\- Bloomer (15) distinctly 

 shows that it is somewhat related to Solecurtellus. It has dis- 

 tinctly been shown by Bloomer [(15), p. 219; (12), p. 80] that 

 S. rufus is anatomically more closely related to S. dombeyi than 

 to T. gibbus, and that the two genera resemble each other in the 

 structure of the gills. 



