CESTODE AND NEMATODE PARASITES. 53 



Phyllobothriuin pamiuicrum, n. sp. Plate III., tigs. 34 and 35. 



This is the second small Phyllohothrlum found in the intestine of Carcharias 

 melanopterus. 



Two specimens which were mounted measured 13 millims. and 11 millions, respec- 

 tively. The greatest width was 0"5 nhllim. The head and neck are very 

 transparent. The head carries four sessile, rather crumpled bothridia, in which there 

 are no areolas. The edges of the bothridia are decidedly crumpled. Many muscles 

 run down from the head through the neck, which is long (Plate III., fig. 35). 



The strobilization is peculiar. There is no sign of the gradual differentiation of the 

 proglottis first as a narrow band, which broadens as it passes backward, but the most 

 anterior segment is almost as large as those which succeed it perhaps one ought to 

 say, those which precede it (Plate III., fig. 34). The proglottides have straight 

 parallel sides and straight parallel ends, and their hinder edges do not overhang the 

 front edges of the next behind. The reproductive pores are lateral and confined to 

 one side. The posterior segments are three times as long as they are broad, some- 

 times even a little longer. 



The diagnosis of Phyllobothrium pammicrum may run : 



Length 11 millims. to 13 millims. Greatest breadth 0'5 millim. Head with four 

 sessile bothridia crumpled, with no areola. Neck long. Proglottides when they first 

 appear are almost of full size, with straight sides and ends, and no overlapping. 

 Byproduct ive pores lateral and on one side only. 



Habitat : In the intestine of Carcharias melanopterus. 



Tetrarhynchus carcharidis, n. sp. Plate III., figs. 36 and 37. 



A minute form of Tetrarhynchus was found in the intestine of a Carcharias 

 melanopterus taken in Dutch Bay on January 5, 1905. The length usually 9 millims. 

 The anterior end of the body is extremely thin and whipdike ; the body, however, 

 thickens posteriorly until the two last proglottides are 0'5 millim. in thickness. 

 These proglottides are very long, 1 - 5 millims. and 2 millims. respectively. 



The head is minute, and in stained specimens takes little stain. The two lappets 

 are smooth at their edges, not wrinkled, and with no indentation or sign of division 

 into two. The proboscides are very fine, and bear a number of spines, not hooks. 

 These spines are thicker at the base than at their free end ; they all point backwards. 

 They are very minute, and seem to be arranged in slightly oblique rings. The 

 proboscis-tubes are very closely coiled, and end in the four muscular bulbs, which 

 hardly occupy one fifth of the total head length. The whole head seems to be dusted 

 through with granules (Plate III., fig. 37). 



There is no neck. The narrow, band-like proglottides appear immediately behind 

 the head, and they and even the hinder proglottides are separated by quite clear 

 transparent divisions. There are only some eighteen or nineteen proglottides, and we 



