i'72 CEYLON MARINE BIOLOGICAL REPORTS. 



Bhynchoholhrium, sp. III. (Plate II., Figs. 31 and 32.) 



Lnvvae of a third species of Rhynchdbothrium were obtained from cysts found on the mesenteries of 

 Balistes mitts. 



The cysts are long, cylindrical, firm, and opaque. They measure 14 mm. by 2 mm. The larvae 

 measure 2 mm. by 6 mm. The botliridia are ckcular in outline, concave, with thickened overhanging 

 rims, and are indented anteriorly and posteriorly, and each bothi-idium is divided mto two halves by a 

 shallow ridge riuinmg parallel to the body. They measiue one-third the length of the head and neck. 

 The proboscis sacs also measm-e about one-third the length of the head and neck. Tlie proboscides are 

 spirally coiled, and do not protrude to the exterior, the pores being closed. The spines are of various sizes 

 and shapes. Some have narrow bases, and are long and slender, ^rith the extremity bent at right angles. 

 Others are short with a broad base, and are strongly recurved. The arrangement of the hooks could 

 not be ascertained. 



Habitat. — Tlie mesenteries of Balistes mitis. Twenty-seven specimens. November, 1910. 



Rhynchobothrium, spp. 

 I include here a note with figures of single specimens of larvse obtained from cysts. 



Species'A. Plate III., Fig. 33. Prom oval cysts 9 mm. long and 3 mm. broad. Larva measuring 

 mm. by •? mm. A single specimen from the mesenteries of Serramis undulosus. February 27, 1910. 



Species B. Plate III. , Fig. 34. From oval cysts 7 mm. long and 2 mm. broad. Larva measuring 

 5 mm. long and '4 mm. broad. A single specimen from the mesenteries of Lutjanus gibbu-s. December 

 8, 1910. 



Species C. Plate III., Fig. 35. From oval cysts 4 mm. long and 1-2 mm. broad. Larva measuring 

 3 mm. long and • 3 mm. broad. A single specimen from Pseitoc/es cr«7»ci. February 27, 1911. Possibly 

 tills is the same species as species B. 



In none of these larvae was the nature of the spmes on the proboscides determmed, as this could 

 not be done without destroying the specimens. 



Rhynchobothrium rossii, n. sp. (Plate III., Figs. 36, 37, 38, and 39.) 



This worm, which measures 60 mm. long, consists of a very small head and a whip-like body, which 

 broadens and thickens greatly posteriorly. Except the last 6-11 proglottides, which are pigmented 

 brown, the rest of the worm is clear and very transparent. The head consists of two somewhat oblong, 

 concave, undivided bothridia, ^^'ith thickened rims, Avhich are slightly indented both posteriorly and 

 anteriorly, and measure approximately -5 mm. long. They diverge slightly posteriorly. The head and 

 neck, which are -4 mm. broad and 2 mm. long, pass into the strobila without any alteration in breadth, 

 and thus, except under a magnification of 30 diameters, the posterior termination of the proboscis sacs 

 caiuiot be seen. The bothridia and proboscis sacs together measure half the length of the head and neck. 

 The proboscides are loosely coiled spuaUy. The hooks are aiTanged spirally and have a broad base, and 

 are short and strongly recurved. The whole surface of the head, neck, and fii'st proglottides is marked 

 bj' a series of straight lines crossing each other and givmg a characteristic appearance. The head and 

 neck together measure 2 mm. There is a short unsegmented portion between the proboscis sacs and the 

 first proglottides. The first segments are very crowded, shallow, and much broader than long. They 

 elongate verj' gradually. About one-third the length of the worm, from the posterior extremity, the 

 segments thicken and become pigmented and opaque. The last segments measure 2-5 mm. long, 

 breadth 2 mm. The proglottides are not sahent. The genital apertm-es are lateral and irregularly 

 alternate. 



The diagnosis of Rhynchobothrium rossii, n. sp., is as follows : — 



Long and fairly stout worms, 60 mm. long and a maximum breadth of 2 mm. The head is very 

 small, and consists of two somewhat oblong, concave, midi\'ided bothridia, ^vith thickened rims, which 

 are sUghtly indented both anteriorly and posteriorly. Each bothridium is -4 mm. long. Neck not 

 B'woUen where the proboscis sacs occui'. Head and neck 2 mm. long. The hooks on the proboscides are 

 arranged spirally, and are all alike. They are small, short, stout, with broad bases, and are strongly 



