28 PROCEEDINGS OF THE NATIONAL MUSEUM. tou 55. 



be an occasional parasite, developing to a certain stage at least. 

 Dramard and Benoit-Bazille (1905) have recorded T. j^isiformis 

 from Felis tigris. [Since the above was v^^ritten, Ackert and Grant 

 (1917) have developed immature T. pisiformis^ up to 22 mm. long, 

 in kittens, by feeding Cyst. pisifor?nis.] 



Some of the maximum measurements given in the specific diag- 

 nosis of this species are cited from Deflfke (1891«), and in the writer's 

 experience are much in excess of the usual maximum measurements. 

 Stevenson (1904) has noted that some of Defflie's measurements are 

 not substantiated by his illustrations. This is especially true of the 

 measurements of the cirrus pouch. 



In counting the testes in toto mounts, a count of 300 is apt to be ob- 

 tained rather than 400 to 500, but this is probably due to the fact 

 that the testes are in two strata and that some overlie others. 



It is commonly stated that this species has 8 to 10 lateral branches 

 on each side of the main uterine stem. In this case, as in the case of 

 other species of tapeworms examined by the present writer, the num- 

 ber of lateral branches of the uterus may be larger. Stained and 

 mounted specimens may show as many as 14 branches, exclusive of 

 the terminal anterior and posterior digitations of the main uterine 

 stem. 



TAENIA HYDATIGENA Pallas, 1766. 



Synonyms. — Lurribricus hydropicus Tyson, 1691a, pre-Linnaean ; 

 Hydra hydatula Linnaeus, 1767a:; Vermis vesicularis eremita Bloch, 

 1780a; Hydatigena orbicularis Goeze, 1782a; Taenia margvnata 

 Batsch, 1786a; Cysticercus tenuicolli'i Rudolphi, 1810a. (For addi- 

 tional synonyms, see Stiles and Stevenson, 1905a.) 



Specific diagnosis. — Taenia: Head variable in shape, reniform, 

 spherical, cylindrical or truncated pyramidal with the square to ob- 

 long base of the pyramid constituting the rostellar face of the head, 

 and with a head diameter of about 1 mm. Rostellum with a double 

 crown of 26 to 44 hooks. The large hooks (fig. 34) are 170 to 220 (i. 

 long. They have a blade of moderate curvature; the handle, viewed 

 from the side, has a rather sinuous contour, with its dorsal and ven- 

 tral margins approximately parallel, and meets the blade dorsally in 

 an obtuse angle ; the guard is actually and relatively long, about 40 [j., 

 and rather narrow, somewhat cylindrical proximally and terminat- 

 ing conically distally, the cylindrical portion sometimes slightly 

 larger at its union with the conical portion, and the guard forming 

 almost a right angle with the ventral outline of the handle. The 

 small hooks are 110 to 160 [x long. They have a strongly curved 

 blade; the handle, viewed from the side, is long, narrow, and 

 curved, the convexity being on the ventral surface ; the guard is long, 

 narrow and cylindrical, viewed from the side, and is much expanded 

 and cordiform to Y-shaped when viewed along the longitudinal axis 



