CESTODE PARASITES. 267 



Rhinebothrium, Linton (11). 



Body articulate. Head continuous with the body or separated by a neck. Neck merging into 



segmented body or separated by a constriction. Bothria four, opposite or in lateral or marginal pairs, 



faces divided into loculi by several or many transverse and one or few longitudinal muscular partitions, 



mounted on slender pedicels, very versatile, unarmed, myzorhynchus none. Genital apertures marginal. 



Rhinebothrium shipleyi, n. sp. (Plate I., Fi^s. 12, 13, and 13a.) 

 The head consists of fom- botbridia borne on long, triangular, flattened, and very versatile stalks. 

 The face of each botliridia is long and narrow, and is divided by transverse septae only into ten unpaired 

 areolas. There is no longitudinal septum. Each bothridium is 1 mm. long, and approximately -3 mm. 

 broad. The ends are rounded, and the whole bothridium is frmged wdth a deUcate u-regular membrane. 

 In the contracted state the bothridia are often roughly semicircular in shape, with the areolas either on the 

 concave or the convex surface. The breadth of the head varies with the state of contraction and with 

 the disposition of the bothridia, but averages about 1 • 8 mm. There is no myzorhynchus. Inxmediately 

 posterior to the head is a swollen bulbous portion, triangular in shape, with the apex passing into the 

 proglottides. There is no neck, although the fu-st few transverse divisions between the proglottides are 

 faint and indistinct. The fu-st segments are shallow, -3 mm. in breadth, and much broader than long, 

 and they continue so up to the last few (6-8) ripe segments, which latter are square, and then slightly longer 

 (1-2 mm.) than broad ( ■ 9 mm.). The largest of our specimens was 60 mm. long, and the smallest 42 mm. 

 Most specimens were wliip-like in appearance, the maximum breadth being attamed at a distance of about 

 20 mm. from the head, and they contmued the same breadth to the end. This anterior part of the worm 

 is apt to be of uneven breadth, which fact is doubtless due to u-regular contraction. The posterior and 

 ripe proglottides in oiu- specimens are of varying shades of a dark brown colour. The genital pores are 

 lateral and irregularly alternate. In some specimens the edges of the proglottides in the middle region of 

 'the worm were slightly salient. 



Habitat. — The spiral valve of Trygon kuhli (Miill. and Henle). Seventy specimens. November and 

 December, 1910. 



The diagnosis of Rhinebothrium shipleyi, n. sp., is as follows : — 



Worms about 60 mm. long. The head consists of four stalked, leaf-like bothridia, which are com- 

 pressed in a plane at right angles to the axis of the worm. The free sm-faces of the bothridia are of an 

 elongated oval shape, and are divided by transverse costse into ten unpahed areolas. This featm-e is 

 distinctive of the species. The pedicels of the bothridia arise fi-om a bulbous portion immediately 

 anterior to the proglottides. There is no myzorhynchus and no neck. Tlie proglottides are broader than 

 long, except the terminal few, which are square, then slightly longer than broad. The genital apertures 

 are lateral and irregularly alternate. About the middle length of the worm tlxe j)roglottides tend to be 

 slightly salient. The maximum breadth of 1 mm. is attained at a distance of about 20 mm. from the head. 



I have pleasure in naming this species in honour of Professor Sliipley, F.R.S., D.Sc, who described 

 the first cestodes from the Ceylon pearl banks, and thus laid the foundations for future work. 



The species described above are only provisionally placed in genus Rhinebothrium, Linton, pending 

 an opportunity for fm-ther work on the Cestoda in general. 



The genus Echeneibothrium, Van Beneden, was described by Diesing as follows : " Body elongated , 

 articulate. Head continuous with the body or separated by a neck, with a terminab retractile nxyzo- 

 rhynchus. Bothria four, opposite, transversely costato-pUcate, sometimes provided with longitucUnal 

 partitions, attached by tlie posterior margin to the head by means of a contractile pedicel, versatile, 

 unarmed. Os in apex of myzorhynchus. Genital apertures marginal." 



It will thus be seen that our species are intermediate between the genera Echeneibothrium and 

 Rhinebothrium. They caimot bo included in the genus Echeneibothrium as described by Diesing on 

 account of the absence of a myzorhynchus, nor can they be included in Linton's genus Rhinebothrium on 

 account of tlie fact that the faces of the botliridia are not divided by " one or a few longitudinal muscular 

 partitions." 



