bloomee: on the anatomy of tagelus. 223 



(Figs. 5 and 6, CO.), whicli is a sac of considerable length passing 

 directly near to tlie ventral surface of the foot, when it curves sharply 

 and proceeds to the dorsal surface of the pedal cavity. The intestine 

 (Figs. 4, 5, and 6, In.) appears as a constricted groove (Fig. 6, In.) 

 on the right side of the caecum of the crystalline style. Xear the 

 distal end of the caecum the intestinal wall becomes complete, and the 

 intestine returns along, and attached for some distance to, the right 

 lateral side of the caecum ; then, leaving it, proceeds with a curve to 

 the dorsal surface of the pyloric division, and, turning posteriorly, 

 goes as the rectum (Fig. 4, E.) over the posterior adductor muscle, 

 around its posterior side to the exhalent chamber (Fig. 4, A.). 



The nervous system apparently is very similar to that of T. gihhus. 



EXPLANATION OF PLATE XIX. 



Tagelus gibbus (Spengler). 

 Fig. 1. View from right side, showing the alimentary canal, etc. Nat. size. 

 ,, 2. Longitudinal section of the stomach, showing the internal structure of the 



left side, x 2. 

 ,, 3. Longitudinal section of the stomach, showing the internal structure of the 

 right side, x 2. 



Tagelus divisus (Spengler). 

 ,, 4. View from right side, showing the alimentary canal, etc. x 2. 

 ,, 5. Longitudinal section of the stomach, showing the internal structure of the 



leftside, x 3. 

 ,, 6. Longitudinal section of the stomach, showing the internal structure of the 



right side, x 3. 



A. anus; A. A. anterior adductor muscle; A.L. anterior or upper lip; B.R. 

 branchial retractor muscle ; C'.C. ciecum of crystalline style ; CD. central division of 

 the stomach ; C.St, cardiac division of the stomach ; E.P. elevator pedis muscle : 

 Ex.S. proximal portion of the exhalent siphonal chamber ; Ex.S'. exhalent siphonal 

 tube; i^. foot; Z'. Z^w. folded portion of the intestine ; 7w. intestine ; Jw. 5. proximal 

 portion of the inhalent siphonal chamber ; In.S'. inhalent siphonal tube ; L. liver ; 

 M. mouth ; M.C musculus cruciformis, a transverse muscle situated veutrally to the 

 siphon; M.L. left mantle-lobe; M.P. developed portion of the muscular ridge, 

 extending a considerable distance across the stomach and representing the continuation 

 of the muscular papilla of Solen ; Oe. oesophagus ; Oe.St. oesophageal division of the 

 stomach; P.A. posterior adductor muscle; P.L. posterior or lower lip; P.L.P. 

 posterior portions of the mantle-lobes, which envelop and are connected anteriorly 

 with the siphon; P.P. protractor pedis muscle; P.P. A. retractor pedis anterior 

 muscle; P.R.P. retractor pedis posterior muscle; P.St, pyloric division of the 

 stomach ; R. rectum ; S.R.M. siphonal retractor muscle ; St. stomach. 



